diff --git a/src/wasm/function-body-decoder-impl.h b/src/wasm/function-body-decoder-impl.h
index 6fd5617ff4..aa1368f609 100644
--- a/src/wasm/function-body-decoder-impl.h
+++ b/src/wasm/function-body-decoder-impl.h
@@ -3175,9 +3175,6 @@ class WasmFullDecoder : public WasmDecoder<validate> {
   }
 
   void BuildSimplePrototypeOperator(WasmOpcode opcode) {
-    if (WasmOpcodes::IsSignExtensionOpcode(opcode)) {
-      RET_ON_PROTOTYPE_OPCODE(se);
-    }
     if (WasmOpcodes::IsAnyRefOpcode(opcode)) {
       RET_ON_PROTOTYPE_OPCODE(anyref);
     }
diff --git a/src/wasm/wasm-feature-flags.h b/src/wasm/wasm-feature-flags.h
index 8b87462af5..870f08deaa 100644
--- a/src/wasm/wasm-feature-flags.h
+++ b/src/wasm/wasm-feature-flags.h
@@ -18,10 +18,9 @@
   V(mv, "multi-value support", false)        \
   V(type_reflection, "wasm type reflection in JS", false)
 
-#define FOREACH_WASM_SHIPPED_FEATURE_FLAG(V)                          \
-  V(bulk_memory, "bulk memory opcodes", true)                         \
-  V(sat_f2i_conversions, "saturating float conversion opcodes", true) \
-  V(se, "sign extension opcodes", true)
+#define FOREACH_WASM_SHIPPED_FEATURE_FLAG(V)  \
+  V(bulk_memory, "bulk memory opcodes", true) \
+  V(sat_f2i_conversions, "saturating float conversion opcodes", true)
 
 #define FOREACH_WASM_FEATURE_FLAG(V)        \
   FOREACH_WASM_EXPERIMENTAL_FEATURE_FLAG(V) \
diff --git a/src/wasm/wasm-opcodes.cc b/src/wasm/wasm-opcodes.cc
index 97a5197351..5f5a9fd407 100644
--- a/src/wasm/wasm-opcodes.cc
+++ b/src/wasm/wasm-opcodes.cc
@@ -422,19 +422,6 @@ bool WasmOpcodes::IsUnconditionalJump(WasmOpcode opcode) {
   }
 }
 
-bool WasmOpcodes::IsSignExtensionOpcode(WasmOpcode opcode) {
-  switch (opcode) {
-    case kExprI32SExtendI8:
-    case kExprI32SExtendI16:
-    case kExprI64SExtendI8:
-    case kExprI64SExtendI16:
-    case kExprI64SExtendI32:
-      return true;
-    default:
-      return false;
-  }
-}
-
 bool WasmOpcodes::IsAnyRefOpcode(WasmOpcode opcode) {
   switch (opcode) {
     case kExprRefNull:
diff --git a/src/wasm/wasm-opcodes.h b/src/wasm/wasm-opcodes.h
index f8387a8156..74f3e7046c 100644
--- a/src/wasm/wasm-opcodes.h
+++ b/src/wasm/wasm-opcodes.h
@@ -220,15 +220,14 @@ bool IsJSCompatibleSignature(const FunctionSig* sig, const WasmFeatures&);
   V(I32ReinterpretF32, 0xbc, i_f) \
   V(I64ReinterpretF64, 0xbd, l_d) \
   V(F32ReinterpretI32, 0xbe, f_i) \
-  V(F64ReinterpretI64, 0xbf, d_l)
+  V(F64ReinterpretI64, 0xbf, d_l) \
+  V(I32SExtendI8, 0xc0, i_i)      \
+  V(I32SExtendI16, 0xc1, i_i)     \
+  V(I64SExtendI8, 0xc2, l_l)      \
+  V(I64SExtendI16, 0xc3, l_l)     \
+  V(I64SExtendI32, 0xc4, l_l)
 
-#define FOREACH_SIMPLE_PROTOTYPE_OPCODE(V) \
-  V(I32SExtendI8, 0xc0, i_i)               \
-  V(I32SExtendI16, 0xc1, i_i)              \
-  V(I64SExtendI8, 0xc2, l_l)               \
-  V(I64SExtendI16, 0xc3, l_l)              \
-  V(I64SExtendI32, 0xc4, l_l)              \
-  V(RefIsNull, 0xd1, i_r)
+#define FOREACH_SIMPLE_PROTOTYPE_OPCODE(V) V(RefIsNull, 0xd1, i_r)
 
 // For compatibility with Asm.js.
 #define FOREACH_ASMJS_COMPAT_OPCODE(V) \
@@ -669,7 +668,6 @@ class V8_EXPORT_PRIVATE WasmOpcodes {
   static FunctionSig* AsmjsSignature(WasmOpcode opcode);
   static bool IsPrefixOpcode(WasmOpcode opcode);
   static bool IsControlOpcode(WasmOpcode opcode);
-  static bool IsSignExtensionOpcode(WasmOpcode opcode);
   static bool IsAnyRefOpcode(WasmOpcode opcode);
   static bool IsThrowingOpcode(WasmOpcode opcode);
   // Check whether the given opcode always jumps, i.e. all instructions after
diff --git a/test/cctest/wasm/test-run-wasm-sign-extension.cc b/test/cctest/wasm/test-run-wasm-sign-extension.cc
index 1514699db8..d6a6478f45 100644
--- a/test/cctest/wasm/test-run-wasm-sign-extension.cc
+++ b/test/cctest/wasm/test-run-wasm-sign-extension.cc
@@ -11,7 +11,6 @@ namespace internal {
 namespace wasm {
 
 WASM_EXEC_TEST(I32SExtendI8) {
-  EXPERIMENTAL_FLAG_SCOPE(se);
   WasmRunner<int32_t, int32_t> r(execution_tier);
   BUILD(r, WASM_I32_SIGN_EXT_I8(WASM_GET_LOCAL(0)));
   CHECK_EQ(0, r.Call(0));
@@ -22,7 +21,6 @@ WASM_EXEC_TEST(I32SExtendI8) {
 }
 
 WASM_EXEC_TEST(I32SExtendI16) {
-  EXPERIMENTAL_FLAG_SCOPE(se);
   WasmRunner<int32_t, int32_t> r(execution_tier);
   BUILD(r, WASM_I32_SIGN_EXT_I16(WASM_GET_LOCAL(0)));
   CHECK_EQ(0, r.Call(0));
@@ -33,7 +31,6 @@ WASM_EXEC_TEST(I32SExtendI16) {
 }
 
 WASM_EXEC_TEST(I64SExtendI8) {
-  EXPERIMENTAL_FLAG_SCOPE(se);
   WasmRunner<int64_t, int64_t> r(execution_tier);
   BUILD(r, WASM_I64_SIGN_EXT_I8(WASM_GET_LOCAL(0)));
   CHECK_EQ(0, r.Call(0));
@@ -44,7 +41,6 @@ WASM_EXEC_TEST(I64SExtendI8) {
 }
 
 WASM_EXEC_TEST(I64SExtendI16) {
-  EXPERIMENTAL_FLAG_SCOPE(se);
   WasmRunner<int64_t, int64_t> r(execution_tier);
   BUILD(r, WASM_I64_SIGN_EXT_I16(WASM_GET_LOCAL(0)));
   CHECK_EQ(0, r.Call(0));
@@ -55,7 +51,6 @@ WASM_EXEC_TEST(I64SExtendI16) {
 }
 
 WASM_EXEC_TEST(I64SExtendI32) {
-  EXPERIMENTAL_FLAG_SCOPE(se);
   WasmRunner<int64_t, int64_t> r(execution_tier);
   BUILD(r, WASM_I64_SIGN_EXT_I32(WASM_GET_LOCAL(0)));
   CHECK_EQ(0, r.Call(0));
diff --git a/test/unittests/wasm/function-body-decoder-unittest.cc b/test/unittests/wasm/function-body-decoder-unittest.cc
index be6ad97552..22411f8a21 100644
--- a/test/unittests/wasm/function-body-decoder-unittest.cc
+++ b/test/unittests/wasm/function-body-decoder-unittest.cc
@@ -1347,7 +1347,6 @@ TEST_F(FunctionBodyDecoderTest, MacrosInt64) {
 }
 
 TEST_F(FunctionBodyDecoderTest, AllSimpleExpressions) {
-  WASM_FEATURE_SCOPE(se);
   WASM_FEATURE_SCOPE(anyref);
 // Test all simple expressions which are described by a signature.
 #define DECODE_TEST(name, opcode, sig)                      \