diff --git a/barretenberg/cpp/scripts/wasmtime.sh b/barretenberg/cpp/scripts/wasmtime.sh
index 3ad657d5798d..3e4032043ab8 100755
--- a/barretenberg/cpp/scripts/wasmtime.sh
+++ b/barretenberg/cpp/scripts/wasmtime.sh
@@ -5,6 +5,7 @@ set -eu
 export WASMTIME_BACKTRACE_DETAILS=1
 exec wasmtime run \
   -Wthreads=y \
+  -Wunknown-imports-trap=y \
   -Sthreads=y \
   ${HARDWARE_CONCURRENCY:+--env HARDWARE_CONCURRENCY} \
   --env HOME \
diff --git a/barretenberg/cpp/src/barretenberg/env/throw_or_abort_impl.cpp b/barretenberg/cpp/src/barretenberg/env/throw_or_abort_impl.cpp
index 2cc76037a1f5..fdff0104f6e3 100644
--- a/barretenberg/cpp/src/barretenberg/env/throw_or_abort_impl.cpp
+++ b/barretenberg/cpp/src/barretenberg/env/throw_or_abort_impl.cpp
@@ -1,3 +1,14 @@
+// In WASM builds, throw_or_abort_impl is provided by the JavaScript environment
+// (declared as WASM_IMPORT in throw_or_abort_impl.hpp). The JS implementation
+// throws a catchable JS Error with the error message.
+//
+// For non-JS WASM runtimes (wasmtime), the import must also be provided.
+// See barretenberg/cpp/scripts/wasmtime.sh for the wasmtime configuration.
+//
+// We guard out the C++ definition so the JS import is used instead of being
+// shadowed by the local definition (which would call std::abort).
+#ifndef __wasm__
+
 #include "barretenberg/common/log.hpp"
 #include "barretenberg/common/wasm_export.hpp"
 #include <stdexcept>
@@ -27,3 +38,5 @@ WASM_EXPORT void throw_or_abort_impl [[noreturn]] (const char* err)
     abort_with_message(err);
 #endif
 }
+
+#endif // !__wasm__