diff --git a/Cargo.lock b/Cargo.lock
index ba3bfc17..54e8f837 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -110,12 +110,13 @@ checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"
 
 [[package]]
 name = "fancy-regex"
-version = "0.12.0"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7493d4c459da9f84325ad297371a6b2b8a162800873a22e3b6b6512e61d18c05"
+checksum = "531e46835a22af56d1e3b66f04844bed63158bc094a628bec1d321d9b4c44bf2"
 dependencies = [
  "bit-set",
- "regex",
+ "regex-automata",
+ "regex-syntax",
 ]
 
 [[package]]
@@ -336,18 +337,6 @@ dependencies = [
  "crossbeam-utils",
 ]
 
-[[package]]
-name = "regex"
-version = "1.10.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b91213439dad192326a0d7c6ee3955910425f441d7038e0d6933b0aec5c4517f"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-automata",
- "regex-syntax",
-]
-
 [[package]]
 name = "regex-automata"
 version = "0.4.7"
diff --git a/rten-text/Cargo.toml b/rten-text/Cargo.toml
index 742237da..334f036f 100644
--- a/rten-text/Cargo.toml
+++ b/rten-text/Cargo.toml
@@ -13,7 +13,7 @@ include = ["/src", "/README.md"]
 crate-type = ["lib"]
 
 [dependencies]
-fancy-regex = { version = "0.12.0", default-features = false, features = ["std", "unicode"] }
+fancy-regex = { version = "0.13.0", default-features = false, features = ["std", "unicode"] }
 unicode_categories = "0.1.1"
 unicode-normalization = "0.1.22"
 serde = { workspace = true, features = ["derive"] }
diff --git a/rten-text/src/tokenizers.rs b/rten-text/src/tokenizers.rs
index 5832789e..e2dbadf2 100644
--- a/rten-text/src/tokenizers.rs
+++ b/rten-text/src/tokenizers.rs
@@ -595,7 +595,7 @@ pub enum TokenizerError {
     InvalidTokenId(TokenId),
 
     /// Splitting the input with a regex failed.
-    RegexSplitFailed(fancy_regex::Error),
+    RegexSplitFailed(Box<fancy_regex::Error>),
 
     /// There was an error parsing a byte sequence as a UTF-8 string.
     ///
diff --git a/rten-text/src/tokenizers/bpe.rs b/rten-text/src/tokenizers/bpe.rs
index b33c0cc9..8fe41974 100644
--- a/rten-text/src/tokenizers/bpe.rs
+++ b/rten-text/src/tokenizers/bpe.rs
@@ -18,7 +18,7 @@ pub enum BpeError {
     InvalidMergeEntry(String),
 
     /// The regex for splitting tokens is invalid.
-    InvalidPattern(fancy_regex::Error),
+    InvalidPattern(Box<fancy_regex::Error>),
 
     /// An entry in the vocab (token string to ID map) is not either a known
     /// special token or an entry in the merge list.
@@ -289,7 +289,7 @@ impl Bpe {
         vocab: Option<HashMap<EncodedBytes, TokenId>>,
         added_tokens: HashMap<TokenId, String>,
     ) -> Result<Bpe, BpeError> {
-        let splitter = Regex::new(pattern).map_err(BpeError::InvalidPattern)?;
+        let splitter = Regex::new(pattern).map_err(|err| BpeError::InvalidPattern(err.into()))?;
 
         let mut builder = BpeBuilder::new();
         builder.add_merges(merges)?;
@@ -428,7 +428,7 @@ impl Encoder for Bpe {
         on_token: &mut dyn FnMut(usize, TokenId),
     ) -> Result<(), TokenizerError> {
         for piece in self.splitter.find_iter(text) {
-            let piece = piece.map_err(TokenizerError::RegexSplitFailed)?;
+            let piece = piece.map_err(|err| TokenizerError::RegexSplitFailed(err.into()))?;
             if piece.range().is_empty() {
                 continue;
             }