diff --git a/include/ncs3sdk.h b/include/ncs3sdk.h
index 50f2ad2708..adc7e456be 100644
--- a/include/ncs3sdk.h
+++ b/include/ncs3sdk.h
@@ -15,7 +15,7 @@
 /* Track the server type, if known */
 typedef enum NCS3SVC {NCS3UNK=0, /* unknown */
                  NCS3=1,    /* s3.amazon.aws */
-		 NCS3GS=0   /* storage.googleapis.com */
+		 NCS3GS=2   /* storage.googleapis.com */
 } NCS3SVC;
 
 typedef struct NCS3INFO {
diff --git a/libdispatch/ds3util.c b/libdispatch/ds3util.c
index aab8fe987b..5ccd01f9e7 100644
--- a/libdispatch/ds3util.c
+++ b/libdispatch/ds3util.c
@@ -110,17 +110,24 @@ NC_s3urlrebuild(NCURI* url, NCS3INFO* s3, NCURI** newurlp)
     /* split the path by "/" */
     if((stat = NC_split_delim(url->path,'/',pathsegments))) goto done;
 
-    /* Distinguish path-style from virtual-host style from s3: and from other.
-       Virtual: https://<bucket-name>.s3.<region>.amazonaws.com/<path>				(1)
-            or: https://<bucket-name>.s3.amazonaws.com/<path> -- region defaults (to us-east-1)	(2)
-       Path: https://s3.<region>.amazonaws.com/<bucket-name>/<path>				(3)
-         or: https://s3.amazonaws.com/<bucket-name>/<path> -- region defaults to us-east-1      (4)
-       S3: s3://<bucket-name>/<path>								(5)
-       Google: https://storage.googleapis.com/<bucket-name>/<path>				(6)
-           or: gs3://<bucket-name>/<path>							(7)
-       Other: https://<host>/<bucket-name>/<path>						(8)
-    */
-    if(url->host == NULL || strlen(url->host) == 0)
+	/* Distinguish path-style from virtual-host style from s3: and from other.
+	Virtual:
+		(1) https://<bucket-name>.s3.<region>.amazonaws.com/<path>
+		(2) https://<bucket-name>.s3.amazonaws.com/<path> -- region defaults (to us-east-1)
+	Path:
+		(3) https://s3.<region>.amazonaws.com/<bucket-name>/<path>
+		(4) https://s3.amazonaws.com/<bucket-name>/<path> -- region defaults to us-east-1
+	S3:
+		(5) s3://<bucket-name>/<path>
+	Google:
+		(6) https://storage.googleapis.com/<bucket-name>/<path>
+		(7) gs3://<bucket-name>/<path>
+	Other:
+		(8) https://<host>/<bucket-name>/<path>
+		(9) https://<bucket-name>.s3.<region>.domain.example.com/<path>
+		(10)https://s3.<region>.example.com/<bucket>/<path>
+	*/
+	if(url->host == NULL || strlen(url->host) == 0)
         {stat = NC_EURL; goto done;}
 
     /* Reduce the host to standard form such as s3.amazonaws.com by pulling out the
@@ -168,12 +175,21 @@ NC_s3urlrebuild(NCURI* url, NCS3INFO* s3, NCURI** newurlp)
         /* region is unknown */
 	/* bucket is unknown at this point */
 	svc = NCS3GS;
-    } else { /* Presume Format (8) */
-        if((host = strdup(url->host))==NULL)
-	    {stat = NC_ENOMEM; goto done;}
-        /* region is unknown */
-	/* bucket is unknown */
-    }
+    } else { /* Presume Formats (8),(9),(10) */
+		if (nclistlength(hostsegments) > 3 && strcasecmp(nclistget(hostsegments, 1), "s3") == 0){
+			bucket = nclistremove(hostsegments, 0);
+			region = nclistremove(hostsegments, 2);
+			host = strdup(url->host + sizeof(bucket) + 1);
+		}else{
+			if (nclistlength(hostsegments) > 2 && strcasecmp(nclistget(hostsegments, 0), "s3") == 0){
+				region = nclistremove(hostsegments, 1);
+			}
+			if ((host = strdup(url->host)) == NULL){
+				stat = NC_ENOMEM;
+				goto done;
+			}
+		}
+	}
 
     /* region = (1) from url, (2) s3->region, (3) default */
     if(region == NULL && s3 != NULL)
diff --git a/unit_test/CMakeLists.txt b/unit_test/CMakeLists.txt
index 59f04127c3..c08055d93e 100644
--- a/unit_test/CMakeLists.txt
+++ b/unit_test/CMakeLists.txt
@@ -14,6 +14,7 @@
 # run on Windows.
 
 SET(UNIT_TESTS test_ncuri)
+add_bin_test(unit_test test_ncuri)
 
 IF(USE_X_GETOPT)
   SET(XGETOPTSRC "${CMAKE_CURRENT_SOURCE_DIR}/../libdispatch/XGetopt.c")
diff --git a/unit_test/test_ncuri.c b/unit_test/test_ncuri.c
index 56d1a98f14..dd0dbf7891 100644
--- a/unit_test/test_ncuri.c
+++ b/unit_test/test_ncuri.c
@@ -12,6 +12,9 @@ Test the ncuri parsing
 #include <string.h>
 #include "netcdf.h"
 #include "ncuri.h"
+#ifdef NETCDF_ENABLE_S3
+#include "ncpathmgr.h" // to initialize global state needed by NC_s3urlrebuild
+#endif
 
 typedef struct Test {
     char* url;
@@ -47,6 +50,34 @@ static Test TESTS[] = {
 {NULL,NULL}
 };
 
+#if defined(NETCDF_ENABLE_S3)
+static Test S3TESTS[] = {
+//Virtual
+	{"https://<bucket-name>.s3.<region>.amazonaws.com/<path>","https://s3.<region>.amazonaws.com/<bucket-name>/<path>#mode=s3"},
+	{"https://<bucket-name>.s3.amazonaws.com/<path>","https://s3.us-east-1.amazonaws.com/<bucket-name>/<path>#mode=s3"},
+//Path
+	{"https://s3.<region>.amazonaws.com/<bucket-name>/<path>","https://s3.<region>.amazonaws.com/<bucket-name>/<path>#mode=s3"},
+	{"https://s3.amazonaws.com/<bucket-name>/<path>","https://s3.us-east-1.amazonaws.com/<bucket-name>/<path>#mode=s3"},
+//s3
+	{"s3://<bucket-name>/<path>","https://s3.us-east-1.amazonaws.com/<bucket-name>/<path>#mode=s3"},
+//Google
+	{"https://storage.googleapis.com/<bucket-name>/<path>","https://storage.googleapis.com/<bucket-name>/<path>#mode=s3"},
+	{"gs3://<bucket-name>/<path>","https://storage.googleapis.com/<bucket-name>/<path>#mode=s3"},
+//Other
+// (8) https://<host>/<bucket-name>/<path>
+	{"https://<host>/<bucket>/path/2/resource/#mode=s3,zarr", "https://<host>/<bucket>/path/2/resource#mode=s3,zarr"},
+// (9) https://<bucket-name>.s3.<region>.domain.example.com/<path>
+	{"https://<bucket>.s3.<region>.<domain>/path/2/resource/#mode=s3,zarr", "https://s3.<region>.<domain>/<bucket>/path/2/resource#mode=s3,zarr"},
+// (10)https://s3.<region>.example.com/<bucket>/<path>
+	{"https://s3.<region>.example.com/bucket/path/2/resource/#mode=s3,zarr", "https://s3.<region>.example.com/bucket/path/2/resource#mode=s3,zarr"},
+	{"https://s3.example.com/bucket/path/2/resource/#mode=s3,zarr", "https://s3.example.com/bucket/path/2/resource#mode=s3,zarr"},
+	{"https://server.example.com/bucket/path/2/resource#mode=s3", "https://server.example.com/bucket/path/2/resource#mode=s3"},
+	{"https://prefix.<bucket>.s3.localhost.example.cloud/path/2/resource#mode=s3", "https://prefix.<bucket>.s3.localhost.example.cloud/path/2/resource#mode=s3"},
+	{"https://<bucket>.s3.<region>.localhost/path/2/resource#mode=s3", "https://s3.<region>.localhost/<bucket>/path/2/resource#mode=s3"},
+	{NULL,NULL}
+};
+#endif
+
 /* Tests that should fail */
 static char* XTESTS[] = {
 "[dap4http://localhost:8081/x",
@@ -92,6 +123,43 @@ main(int argc, char** argv)
 	}
     }
 
+#ifdef NETCDF_ENABLE_S3
+	nc_initialize();
+	for(index=0, test=S3TESTS;test->url;test++,index++) {
+		int ret = 0;
+		NCURI* uri = NULL;
+		ret = ncuriparse(test->url,&uri);
+		if(ret != NC_NOERR) {
+			fprintf(stderr,"Parse fail: %s\n",test->url);
+			failcount++;
+		} else {
+			int iss3 = NC_iss3(uri,NULL);
+			if(iss3 != 0){
+				NCURI * newuri = NULL;
+				if(NC_s3urlrebuild(uri,NULL,&newuri)){
+					fprintf(stderr, "Could not reinterpret url [%d] with s3urlrebuild: %s\n",index,test->url);
+					fprintf(stderr,"Mismatch: [%d] expected=|%s| actual=|%s|\n",index,test->expected,"NULL");
+					failcount ++;
+				}else{
+					char* built = ncuribuild(newuri,NULL,NULL,NCURIALL);
+					if(built == NULL) {
+						fprintf(stderr,"Build fail: %s\n",test->url);
+						failcount++;
+					} else {
+						if(strcmp(test->expected,built) != 0) {
+							fprintf(stderr,"Mismatch: [%d] expected=|%s| actual=|%s|\n",index,test->expected,built);
+							failcount++;
+						}
+						free(built);
+					}
+				}
+				ncurifree(newuri);
+			}
+		}
+		ncurifree(uri);
+	}
+	nc_finalize();
+#endif
     fprintf(stderr,"%s test_ncuri\n",failcount > 0 ? "***FAIL":"***PASS");
     return (failcount > 0 ? 1 : 0);
 }