diff --git a/CHANGELOG.md b/CHANGELOG.md
index d43f37ed40..4fe89039e3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -38,6 +38,9 @@
 * Cache results from PackageManager
   [#1288](https://github.com/bugsnag/bugsnag-android/pull/1288)
 
+* Use ring buffer to store breadcrumbs
+  [#1286](https://github.com/bugsnag/bugsnag-android/pull/1286)
+
 ## 5.9.4 (2021-05-26)
 
 * Unity: add methods for setting autoNotify and autoDetectAnrs
diff --git a/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/BreadcrumbFilterTest.kt b/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/BreadcrumbFilterTest.kt
index 678e4009d1..d8092ece01 100644
--- a/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/BreadcrumbFilterTest.kt
+++ b/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/BreadcrumbFilterTest.kt
@@ -24,8 +24,7 @@ class BreadcrumbFilterTest {
         client = generateClient(configuration)
 
         client.leaveBreadcrumb("Hello World")
-
-        assertEquals(1, client.breadcrumbState.store.size)
+        assertEquals(1, client.breadcrumbState.copy().size)
     }
 
     @Test
@@ -36,6 +35,6 @@ class BreadcrumbFilterTest {
 
         client.leaveBreadcrumb("Hello World")
 
-        assertEquals(1, client.breadcrumbState.store.size)
+        assertEquals(1, client.breadcrumbState.copy().size)
     }
 }
diff --git a/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/BreadcrumbStateTest.kt b/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/BreadcrumbStateTest.kt
index 34ff644a55..1f5831ca20 100644
--- a/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/BreadcrumbStateTest.kt
+++ b/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/BreadcrumbStateTest.kt
@@ -31,7 +31,7 @@ class BreadcrumbStateTest {
     fun testClientMethods() {
         client = generateClient()
         client!!.leaveBreadcrumb("Hello World")
-        val store = client!!.breadcrumbState.store
+        val store = client!!.breadcrumbState.copy()
         var count = 0
 
         for (breadcrumb in store) {
diff --git a/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/ClientTest.java b/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/ClientTest.java
index f09093c666..6a460759b8 100644
--- a/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/ClientTest.java
+++ b/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/ClientTest.java
@@ -76,14 +76,14 @@ public void testMaxBreadcrumbs() {
         config.setEnabledBreadcrumbTypes(new HashSet<>(breadcrumbTypes));
         config.setMaxBreadcrumbs(2);
         client = generateClient(config);
-        assertEquals(0, client.breadcrumbState.getStore().size());
+        assertEquals(0, client.breadcrumbState.copy().size());
 
         client.leaveBreadcrumb("test");
         client.leaveBreadcrumb("another");
         client.leaveBreadcrumb("yet another");
-        assertEquals(2, client.breadcrumbState.getStore().size());
+        assertEquals(2, client.breadcrumbState.copy().size());
 
-        Breadcrumb poll = client.breadcrumbState.getStore().poll();
+        Breadcrumb poll = client.breadcrumbState.copy().get(0);
         assertEquals(BreadcrumbType.MANUAL, poll.getType());
         assertEquals("another", poll.getMessage());
     }
@@ -129,7 +129,7 @@ public void testClientBreadcrumbRetrieval() {
         client = generateClient();
         client.leaveBreadcrumb("Hello World");
         List<Breadcrumb> breadcrumbs = client.getBreadcrumbs();
-        List<Breadcrumb> store = new ArrayList<>(client.breadcrumbState.getStore());
+        List<Breadcrumb> store = new ArrayList<>(client.breadcrumbState.copy());
         assertEquals(store, breadcrumbs);
         assertNotSame(store, breadcrumbs);
     }
@@ -153,8 +153,8 @@ public void testBreadcrumbStoreNotModified() {
 
         breadcrumbs.clear(); // only the copy should be cleared
         assertTrue(breadcrumbs.isEmpty());
-        assertEquals(1, client.breadcrumbState.getStore().size());
-        assertEquals("Manual breadcrumb", client.breadcrumbState.getStore().remove().getMessage());
+        assertEquals(1, client.breadcrumbState.copy().size());
+        assertEquals("Manual breadcrumb", client.breadcrumbState.copy().get(0).getMessage());
     }
 
     @Test
diff --git a/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/OnBreadcrumbCallbackStateTest.java b/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/OnBreadcrumbCallbackStateTest.java
index 8ecdb7e136..ecdd889d93 100644
--- a/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/OnBreadcrumbCallbackStateTest.java
+++ b/bugsnag-android-core/src/androidTest/java/com/bugsnag/android/OnBreadcrumbCallbackStateTest.java
@@ -34,7 +34,7 @@ public void setUp() {
         breadcrumbTypes.add(BreadcrumbType.USER);
         configuration.setEnabledBreadcrumbTypes(breadcrumbTypes);
         client = generateClient(configuration);
-        assertEquals(0, client.breadcrumbState.getStore().size());
+        assertEquals(0, client.breadcrumbState.copy().size());
     }
 
     @After
@@ -45,7 +45,7 @@ public void tearDown() {
     @Test
     public void noCallback() {
         client.leaveBreadcrumb("Hello");
-        assertEquals(1, client.breadcrumbState.getStore().size());
+        assertEquals(1, client.breadcrumbState.copy().size());
     }
 
     @Test
@@ -57,7 +57,7 @@ public boolean onBreadcrumb(@NonNull Breadcrumb breadcrumb) {
             }
         });
         client.leaveBreadcrumb("Hello");
-        assertEquals(0, client.breadcrumbState.getStore().size());
+        assertEquals(0, client.breadcrumbState.copy().size());
     }
 
     @Test
@@ -69,7 +69,7 @@ public boolean onBreadcrumb(@NonNull Breadcrumb breadcrumb) {
             }
         });
         client.leaveBreadcrumb("Hello");
-        assertEquals(1, client.breadcrumbState.getStore().size());
+        assertEquals(1, client.breadcrumbState.copy().size());
     }
 
     @Test
@@ -87,7 +87,7 @@ public boolean onBreadcrumb(@NonNull Breadcrumb breadcrumb) {
             }
         });
         client.leaveBreadcrumb("Hello");
-        assertEquals(0, client.breadcrumbState.getStore().size());
+        assertEquals(0, client.breadcrumbState.copy().size());
     }
 
     @Test
@@ -161,7 +161,7 @@ public boolean onBreadcrumb(@NonNull Breadcrumb breadcrumb) {
         client.leaveBreadcrumb("Hello");
         client.removeOnBreadcrumb(cb);
         client.leaveBreadcrumb("Hello");
-        assertEquals(1, client.breadcrumbState.getStore().size());
+        assertEquals(1, client.breadcrumbState.copy().size());
     }
 
 }
diff --git a/bugsnag-android-core/src/main/java/com/bugsnag/android/BreadcrumbState.kt b/bugsnag-android-core/src/main/java/com/bugsnag/android/BreadcrumbState.kt
index a8882b8c18..331ca721a5 100644
--- a/bugsnag-android-core/src/main/java/com/bugsnag/android/BreadcrumbState.kt
+++ b/bugsnag-android-core/src/main/java/com/bugsnag/android/BreadcrumbState.kt
@@ -1,41 +1,41 @@
 package com.bugsnag.android
 
 import java.io.IOException
-import java.util.Queue
-import java.util.concurrent.ConcurrentLinkedQueue
+import java.util.concurrent.atomic.AtomicInteger
 
+/**
+ * Stores breadcrumbs added to the [Client] in a ring buffer. If the number of breadcrumbs exceeds
+ * the maximum configured limit then the oldest breadcrumb in the ring buffer will be overwritten.
+ *
+ * When the breadcrumbs are required for generation of an event a [List] is constructed and
+ * breadcrumbs added in the order of their addition.
+ */
 internal class BreadcrumbState(
-    maxBreadcrumbs: Int,
-    val callbackState: CallbackState,
-    val logger: Logger
+    private val maxBreadcrumbs: Int,
+    private val callbackState: CallbackState,
+    private val logger: Logger
 ) : BaseObservable(), JsonStream.Streamable {
 
-    val store: Queue<Breadcrumb> = ConcurrentLinkedQueue()
+    /*
+     * We use the `index` as both a pointer to the tail of our ring-buffer, and also as "cheat"
+     * semaphore. When the ring-buffer is being copied - the index is set to a negative number,
+     * which is an invalid array-index. By masking the `expected` value in a `compareAndSet` with
+     * `validIndexMask`: the CAS operation will only succeed if it wouldn't interrupt a concurrent
+     * `copy()` call.
+     */
+    private val validIndexMask: Int = Int.MAX_VALUE
 
-    private val maxBreadcrumbs: Int
-
-    init {
-        when {
-            maxBreadcrumbs > 0 -> this.maxBreadcrumbs = maxBreadcrumbs
-            else -> this.maxBreadcrumbs = 0
-        }
-    }
-
-    @Throws(IOException::class)
-    override fun toStream(writer: JsonStream) {
-        pruneBreadcrumbs()
-        writer.beginArray()
-        store.forEach { it.toStream(writer) }
-        writer.endArray()
-    }
+    private val store = arrayOfNulls<Breadcrumb?>(maxBreadcrumbs)
+    private val index = AtomicInteger(0)
 
     fun add(breadcrumb: Breadcrumb) {
-        if (!callbackState.runOnBreadcrumbTasks(breadcrumb, logger)) {
+        if (maxBreadcrumbs == 0 || !callbackState.runOnBreadcrumbTasks(breadcrumb, logger)) {
             return
         }
 
-        store.add(breadcrumb)
-        pruneBreadcrumbs()
+        // store the breadcrumb in the ring buffer
+        val position = getBreadcrumbIndex()
+        store[position] = breadcrumb
 
         updateState {
             // use direct field access to avoid overhead of accessor method
@@ -48,10 +48,49 @@ internal class BreadcrumbState(
         }
     }
 
-    private fun pruneBreadcrumbs() {
-        // Remove oldest breadcrumbState until new max size reached
-        while (store.size > maxBreadcrumbs) {
-            store.poll()
+    /**
+     * Retrieves the index in the ring buffer where the breadcrumb should be stored.
+     */
+    private fun getBreadcrumbIndex(): Int {
+        while (true) {
+            val currentValue = index.get() and validIndexMask
+            val nextValue = (currentValue + 1) % maxBreadcrumbs
+            if (index.compareAndSet(currentValue, nextValue)) {
+                return currentValue
+            }
+        }
+    }
+
+    /**
+     * Creates a copy of the breadcrumbs in the order of their addition.
+     */
+    fun copy(): List<Breadcrumb> {
+        if (maxBreadcrumbs == 0) {
+            return emptyList()
+        }
+
+        // Set a negative value that stops any other thread from adding a breadcrumb.
+        // This handles reentrancy by waiting here until the old value has been reset.
+        var tail = -1
+        while (tail == -1) {
+            tail = index.getAndSet(-1)
         }
+
+        try {
+            val result = arrayOfNulls<Breadcrumb>(maxBreadcrumbs)
+            store.copyInto(result, 0, tail, maxBreadcrumbs)
+            store.copyInto(result, maxBreadcrumbs - tail, 0, tail)
+            return result.filterNotNull()
+        } finally {
+            index.set(tail)
+        }
+    }
+
+    @Throws(IOException::class)
+    override fun toStream(writer: JsonStream) {
+        val crumbs = copy()
+        writer.beginArray()
+        crumbs.forEach { it.toStream(writer) }
+        writer.endArray()
     }
 }
diff --git a/bugsnag-android-core/src/main/java/com/bugsnag/android/Client.java b/bugsnag-android-core/src/main/java/com/bugsnag/android/Client.java
index 938afa8c38..f7ec7fd4fb 100644
--- a/bugsnag-android-core/src/main/java/com/bugsnag/android/Client.java
+++ b/bugsnag-android-core/src/main/java/com/bugsnag/android/Client.java
@@ -711,7 +711,7 @@ void populateAndNotifyAndroidEvent(@NonNull Event event,
         event.addMetadata("app", appDataCollector.getAppDataMetadata());
 
         // Attach breadcrumbState to the event
-        event.setBreadcrumbs(new ArrayList<>(breadcrumbState.getStore()));
+        event.setBreadcrumbs(breadcrumbState.copy());
 
         // Attach user info to the event
         User user = userState.getUser();
@@ -765,7 +765,7 @@ void notifyInternal(@NonNull Event event,
      */
     @NonNull
     public List<Breadcrumb> getBreadcrumbs() {
-        return new ArrayList<>(breadcrumbState.getStore());
+        return breadcrumbState.copy();
     }
 
     @NonNull
diff --git a/bugsnag-android-core/src/test/java/com/bugsnag/android/BreadcrumbStateTest.kt b/bugsnag-android-core/src/test/java/com/bugsnag/android/BreadcrumbStateTest.kt
index 219c58d697..8153a7c669 100644
--- a/bugsnag-android-core/src/test/java/com/bugsnag/android/BreadcrumbStateTest.kt
+++ b/bugsnag-android-core/src/test/java/com/bugsnag/android/BreadcrumbStateTest.kt
@@ -18,7 +18,15 @@ class BreadcrumbStateTest {
 
     @Before
     fun setUp() {
-        breadcrumbState = BreadcrumbState(20, CallbackState(), NoopLogger)
+        breadcrumbState = createBreadcrumbState(CallbackState())
+    }
+
+    private fun createBreadcrumbState(cbState: CallbackState): BreadcrumbState {
+        return BreadcrumbState(
+            20,
+            cbState,
+            NoopLogger
+        )
     }
 
     /**
@@ -36,46 +44,119 @@ class BreadcrumbStateTest {
             )
         breadcrumbState.add(Breadcrumb(longStr, NoopLogger))
 
-        val crumbs = breadcrumbState.store.toList()
+        val crumbs = breadcrumbState.copy()
         assertEquals(3, crumbs.size)
         assertEquals(longStr, crumbs[2].message)
     }
 
     /**
-     * Verifies that leaving breadcrumbs drops the oldest breadcrumb after reaching the max limit
+     * Verifies that no breadcrumbs are added if the size limit is set to 0
      */
     @Test
-    fun testSizeLimitBeforeAdding() {
+    fun testZeroMaxBreadcrumbs() {
+        breadcrumbState = BreadcrumbState(0, CallbackState(), NoopLogger)
+        breadcrumbState.add(Breadcrumb("1", NoopLogger))
+        breadcrumbState.add(Breadcrumb("2", NoopLogger))
+        assertTrue(breadcrumbState.copy().isEmpty())
+    }
+
+    /**
+     * Verifies that one breadcrumb is added if the size limit is set to 1
+     */
+    @Test
+    fun testOneMaxBreadcrumb() {
+        breadcrumbState = BreadcrumbState(1, CallbackState(), NoopLogger)
+        assertTrue(breadcrumbState.copy().isEmpty())
+
+        breadcrumbState.add(Breadcrumb("A", NoopLogger))
+        assertEquals(1, breadcrumbState.copy().size)
+        assertEquals("A", breadcrumbState.copy()[0].message)
+
+        breadcrumbState.add(Breadcrumb("B", NoopLogger))
+        assertEquals(1, breadcrumbState.copy().size)
+        assertEquals("B", breadcrumbState.copy()[0].message)
+
+        breadcrumbState.add(Breadcrumb("C", NoopLogger))
+        assertEquals(1, breadcrumbState.copy().size)
+        assertEquals("C", breadcrumbState.copy()[0].message)
+    }
+
+    /**
+     * Verifies that the ring buffer can be filled up to the maxBreadcrumbs limit
+     */
+    @Test
+    fun testRingBufferFilled() {
+        breadcrumbState = BreadcrumbState(5, CallbackState(), NoopLogger)
+
+        for (k in 1..5) {
+            breadcrumbState.add(Breadcrumb("$k", NoopLogger))
+        }
+
+        val crumbs = breadcrumbState.copy()
+        assertEquals(5, crumbs.size)
+        assertEquals("1", crumbs[0].message)
+        assertEquals("2", crumbs[1].message)
+        assertEquals("3", crumbs[2].message)
+        assertEquals("4", crumbs[3].message)
+        assertEquals("5", crumbs[4].message)
+    }
+
+    /**
+     * Verifies that the breadcrumbs are in order after the ring buffer wraps around by one
+     */
+    @Test
+    fun testRingBufferExceededByOne() {
         breadcrumbState = BreadcrumbState(5, CallbackState(), NoopLogger)
 
         for (k in 1..6) {
             breadcrumbState.add(Breadcrumb("$k", NoopLogger))
         }
 
-        val crumbs = breadcrumbState.store.toList()
-        assertEquals("2", crumbs.first().message)
-        assertEquals("6", crumbs.last().message)
+        val crumbs = breadcrumbState.copy()
+        assertEquals(5, crumbs.size)
+        assertEquals("2", crumbs[0].message)
+        assertEquals("3", crumbs[1].message)
+        assertEquals("4", crumbs[2].message)
+        assertEquals("5", crumbs[3].message)
+        assertEquals("6", crumbs[4].message)
     }
 
     /**
-     * Verifies that no breadcrumbs are added if the size limit is set to 0
+     * Verifies that the breadcrumbs are in order after the ring buffer wraps around by four
      */
     @Test
-    fun testSetSizeEmpty() {
-        breadcrumbState = BreadcrumbState(0, CallbackState(), NoopLogger)
-        breadcrumbState.add(Breadcrumb("1", NoopLogger))
-        breadcrumbState.add(Breadcrumb("2", NoopLogger))
-        assertTrue(breadcrumbState.store.isEmpty())
+    fun testRingBufferExceededByFour() {
+        breadcrumbState = BreadcrumbState(5, CallbackState(), NoopLogger)
+
+        for (k in 1..9) {
+            breadcrumbState.add(Breadcrumb("$k", NoopLogger))
+        }
+
+        val crumbs = breadcrumbState.copy()
+        assertEquals(5, crumbs.size)
+        assertEquals("5", crumbs[0].message)
+        assertEquals("6", crumbs[1].message)
+        assertEquals("7", crumbs[2].message)
+        assertEquals("8", crumbs[3].message)
+        assertEquals("9", crumbs[4].message)
     }
 
     /**
-     * Verifies that setting a negative size has no effect
+     * Verifies that the breadcrumbs are in order after the ring buffer is filled twice
      */
     @Test
-    fun testSetSizeNegative() {
-        breadcrumbState = BreadcrumbState(-1, CallbackState(), NoopLogger)
-        breadcrumbState.add(Breadcrumb("1", NoopLogger))
-        assertEquals(0, breadcrumbState.store.size)
+    fun testRingBufferFilledTwice() {
+        breadcrumbState = BreadcrumbState(3, CallbackState(), NoopLogger)
+
+        for (k in 1..6) {
+            breadcrumbState.add(Breadcrumb("$k", NoopLogger))
+        }
+
+        val crumbs = breadcrumbState.copy()
+        assertEquals(3, crumbs.size)
+        assertEquals("4", crumbs[0].message)
+        assertEquals("5", crumbs[1].message)
+        assertEquals("6", crumbs[2].message)
     }
 
     /**
@@ -84,7 +165,7 @@ class BreadcrumbStateTest {
     @Test
     fun testDefaultBreadcrumbType() {
         breadcrumbState.add(Breadcrumb("1", NoopLogger))
-        val crumb = requireNotNull(breadcrumbState.store.peek())
+        val crumb = breadcrumbState.copy()[0]
         assertEquals(MANUAL, crumb.type)
     }
 
@@ -97,8 +178,16 @@ class BreadcrumbStateTest {
         for (i in 0..399) {
             metadata[String.format(Locale.US, "%d", i)] = "!!"
         }
-        breadcrumbState.add(Breadcrumb("Rotated Menu", BreadcrumbType.STATE, metadata, Date(0), NoopLogger))
-        assertFalse(breadcrumbState.store.isEmpty())
+        breadcrumbState.add(
+            Breadcrumb(
+                "Rotated Menu",
+                BreadcrumbType.STATE,
+                metadata,
+                Date(0),
+                NoopLogger
+            )
+        )
+        assertFalse(breadcrumbState.copy().isEmpty())
     }
 
     /**
@@ -125,14 +214,18 @@ class BreadcrumbStateTest {
     @Test
     fun testOnBreadcrumbCallback() {
         val breadcrumb = Breadcrumb("Whoops", NoopLogger)
-        breadcrumbState.callbackState.addOnBreadcrumb(
-            OnBreadcrumbCallback {
-                true
-            }
+        val cbState = CallbackState(
+            onBreadcrumbTasks = mutableListOf(
+                OnBreadcrumbCallback {
+                    true
+                }
+            )
         )
+        breadcrumbState = createBreadcrumbState(cbState)
         breadcrumbState.add(breadcrumb)
-        assertEquals(1, breadcrumbState.store.size)
-        assertEquals(breadcrumb, breadcrumbState.store.peek())
+        val copy = breadcrumbState.copy()
+        assertEquals(1, copy.size)
+        assertEquals(breadcrumb, copy.first())
     }
 
     /**
@@ -140,25 +233,31 @@ class BreadcrumbStateTest {
      */
     @Test
     fun testOnBreadcrumbCallbackFalse() {
+        val cbState = CallbackState()
+        breadcrumbState = createBreadcrumbState(cbState)
+
         val requiredBreadcrumb = Breadcrumb("Hello there", NoopLogger)
         breadcrumbState.add(requiredBreadcrumb)
 
-        val breadcrumb = Breadcrumb("Whoops", NoopLogger)
-        breadcrumbState.callbackState.addOnBreadcrumb(
+        cbState.addOnBreadcrumb(
             OnBreadcrumbCallback { givenBreadcrumb ->
                 givenBreadcrumb.metadata?.put("callback", "first")
                 false
             }
         )
-        breadcrumbState.callbackState.addOnBreadcrumb(
+        cbState.addOnBreadcrumb(
             OnBreadcrumbCallback { givenBreadcrumb ->
                 givenBreadcrumb.metadata?.put("callback", "second")
                 true
             }
         )
+
+        val breadcrumb = Breadcrumb("Whoops", NoopLogger)
         breadcrumbState.add(breadcrumb)
-        assertEquals(1, breadcrumbState.store.size)
-        assertEquals(requiredBreadcrumb, breadcrumbState.store.first())
+
+        val copy = breadcrumbState.copy()
+        assertEquals(1, copy.size)
+        assertEquals(requiredBreadcrumb, copy.first())
         assertNotNull(breadcrumb.metadata)
         assertEquals("first", breadcrumb.metadata?.get("callback"))
     }
@@ -168,22 +267,37 @@ class BreadcrumbStateTest {
      */
     @Test
     fun testOnBreadcrumbCallbackException() {
-        val breadcrumb = Breadcrumb("Whoops", NoopLogger)
-        breadcrumbState.callbackState.addOnBreadcrumb(
-            OnBreadcrumbCallback {
-                throw IllegalStateException("Oh no")
-            }
-        )
-        breadcrumbState.callbackState.addOnBreadcrumb(
-            OnBreadcrumbCallback { givenBreadcrumb ->
-                givenBreadcrumb.metadata?.put("callback", "second")
-                true
-            }
+        val cbState = CallbackState(
+            onBreadcrumbTasks = mutableListOf(
+                OnBreadcrumbCallback {
+                    throw IllegalStateException("Oh no")
+                },
+                OnBreadcrumbCallback { givenBreadcrumb ->
+                    givenBreadcrumb.metadata?.put("callback", "second")
+                    true
+                }
+            )
         )
+        breadcrumbState = createBreadcrumbState(cbState)
+
+        val breadcrumb = Breadcrumb("Whoops", NoopLogger)
         breadcrumbState.add(breadcrumb)
-        assertEquals(1, breadcrumbState.store.size)
-        assertEquals(breadcrumb, breadcrumbState.store.peek())
+
+        val copy = breadcrumbState.copy()
+        assertEquals(1, copy.size)
+        assertEquals(breadcrumb, copy[0])
         assertNotNull(breadcrumb.metadata)
         assertEquals("second", breadcrumb.metadata?.get("callback"))
     }
+
+    @Test
+    fun testCopyThenAdd() {
+        breadcrumbState = BreadcrumbState(25, CallbackState(), NoopLogger)
+
+        repeat(1000) { count ->
+            breadcrumbState.add(Breadcrumb("$count", NoopLogger))
+        }
+
+        assertEquals(25, breadcrumbState.copy().size)
+    }
 }
diff --git a/bugsnag-android-core/src/test/java/com/bugsnag/android/ClientFacadeTest.java b/bugsnag-android-core/src/test/java/com/bugsnag/android/ClientFacadeTest.java
index 5685df3ded..94162c04e4 100644
--- a/bugsnag-android-core/src/test/java/com/bugsnag/android/ClientFacadeTest.java
+++ b/bugsnag-android-core/src/test/java/com/bugsnag/android/ClientFacadeTest.java
@@ -22,7 +22,7 @@
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
 
-import java.util.ArrayDeque;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
@@ -148,7 +148,7 @@ public void setUp() {
         when(appDataCollector.generateAppWithState()).thenReturn(app);
         when(appDataCollector.getAppDataMetadata()).thenReturn(new HashMap<String, Object>());
 
-        when(breadcrumbState.getStore()).thenReturn(new ArrayDeque<Breadcrumb>());
+        when(breadcrumbState.copy()).thenReturn(new ArrayList<Breadcrumb>());
         when(userState.getUser()).thenReturn(new User());
         when(callbackState.runOnErrorTasks(any(Event.class), any(Logger.class))).thenReturn(true);
     }
diff --git a/bugsnag-android-core/src/test/java/com/bugsnag/android/DeliveryDelegateTest.kt b/bugsnag-android-core/src/test/java/com/bugsnag/android/DeliveryDelegateTest.kt
index bc9f051eca..9e1b65f449 100644
--- a/bugsnag-android-core/src/test/java/com/bugsnag/android/DeliveryDelegateTest.kt
+++ b/bugsnag-android-core/src/test/java/com/bugsnag/android/DeliveryDelegateTest.kt
@@ -111,7 +111,7 @@ internal class DeliveryDelegateTest {
         assertEquals(DeliveryStatus.DELIVERED, status)
         assertEquals("Sent 1 new event to Bugsnag", logger.msg)
 
-        val breadcrumb = requireNotNull(breadcrumbState.store.peek())
+        val breadcrumb = requireNotNull(breadcrumbState.copy().first())
         assertEquals(BreadcrumbType.ERROR, breadcrumb.type)
         assertEquals("java.lang.RuntimeException", breadcrumb.message)
         assertEquals("java.lang.RuntimeException", breadcrumb.metadata!!["errorClass"])
diff --git a/bugsnag-benchmarks/src/androidTest/java/com/bugsnag/android/benchmark/CriticalPathBenchmarkTest.kt b/bugsnag-benchmarks/src/androidTest/java/com/bugsnag/android/benchmark/CriticalPathBenchmarkTest.kt
index fb3aab1280..2778187aca 100644
--- a/bugsnag-benchmarks/src/androidTest/java/com/bugsnag/android/benchmark/CriticalPathBenchmarkTest.kt
+++ b/bugsnag-benchmarks/src/androidTest/java/com/bugsnag/android/benchmark/CriticalPathBenchmarkTest.kt
@@ -94,6 +94,19 @@ class CriticalPathBenchmarkTest {
         }
     }
 
+    /**
+     * Make a copy of breadcrumbs on the Client (required when generating events)
+     */
+    @Test
+    fun copyBreadcrumbs() {
+        repeat(201) { count ->
+            client.leaveBreadcrumb("Hello world $count")
+        }
+        benchmarkRule.measureRepeated {
+            client.breadcrumbs
+        }
+    }
+
     /**
      * Add a single value to the Client metadata
      */