diff --git a/src/cares_wrap.cc b/src/cares_wrap.cc
index 2dafdf7a650436..997c3ba00d6150 100644
--- a/src/cares_wrap.cc
+++ b/src/cares_wrap.cc
@@ -233,8 +233,7 @@ int ParseGeneralReply(
       status = ares_parse_ptr_reply(buf, len, nullptr, 0, AF_INET, &host);
       break;
     default:
-      CHECK(0 && "Bad NS type");
-      break;
+      UNREACHABLE("Bad NS type");
   }
 
   if (status != ARES_SUCCESS)
@@ -1578,7 +1577,7 @@ void GetAddrInfo(const FunctionCallbackInfo<Value>& args) {
       family = AF_INET6;
       break;
     default:
-      CHECK(0 && "bad address family");
+      UNREACHABLE("bad address family");
   }
 
   auto req_wrap = std::make_unique<GetAddrInfoReqWrap>(env,
@@ -1736,7 +1735,7 @@ void SetServers(const FunctionCallbackInfo<Value>& args) {
         err = uv_inet_pton(AF_INET6, *ip, &cur->addr);
         break;
       default:
-        CHECK(0 && "Bad address family.");
+        UNREACHABLE("Bad address family");
     }
 
     if (err)
diff --git a/src/crypto/crypto_bio.cc b/src/crypto/crypto_bio.cc
index 099b11ee72520d..47045365ceaf81 100644
--- a/src/crypto/crypto_bio.cc
+++ b/src/crypto/crypto_bio.cc
@@ -190,12 +190,9 @@ long NodeBIO::Ctrl(BIO* bio, int cmd, long num,  // NOLINT(runtime/int)
         *reinterpret_cast<void**>(ptr) = nullptr;
       break;
     case BIO_C_SET_BUF_MEM:
-      CHECK(0 && "Can't use SET_BUF_MEM_PTR with NodeBIO");
-      break;
+      UNREACHABLE("Can't use SET_BUF_MEM_PTR with NodeBIO");
     case BIO_C_GET_BUF_MEM_PTR:
-      CHECK(0 && "Can't use GET_BUF_MEM_PTR with NodeBIO");
-      ret = 0;
-      break;
+      UNREACHABLE("Can't use GET_BUF_MEM_PTR with NodeBIO");
     case BIO_CTRL_GET_CLOSE:
       ret = BIO_get_shutdown(bio);
       break;
diff --git a/src/crypto/crypto_keys.cc b/src/crypto/crypto_keys.cc
index f5661ccedad4f7..cc2ff2e631ff77 100644
--- a/src/crypto/crypto_keys.cc
+++ b/src/crypto/crypto_keys.cc
@@ -1393,7 +1393,7 @@ BaseObjectPtr<BaseObject> NativeKeyObject::KeyObjectTransferData::Deserialize(
       key_ctor = env->crypto_key_object_private_constructor();
       break;
     default:
-      CHECK(false);
+      UNREACHABLE();
   }
 
   Local<Value> key;
diff --git a/src/debug_utils.cc b/src/debug_utils.cc
index 69ef383ed22ca8..fadf321c3d925f 100644
--- a/src/debug_utils.cc
+++ b/src/debug_utils.cc
@@ -321,7 +321,7 @@ void CheckedUvLoopClose(uv_loop_t* loop) {
 
   fflush(stderr);
   // Finally, abort.
-  CHECK(0 && "uv_loop_close() while having open handles");
+  UNREACHABLE("uv_loop_close() while having open handles");
 }
 
 void PrintLibuvHandleInformation(uv_loop_t* loop, FILE* stream) {
diff --git a/src/fs_event_wrap.cc b/src/fs_event_wrap.cc
index dafcc065ac612b..048b72666c0570 100644
--- a/src/fs_event_wrap.cc
+++ b/src/fs_event_wrap.cc
@@ -204,7 +204,7 @@ void FSEventWrap::OnEvent(uv_fs_event_t* handle, const char* filename,
   } else if (events & UV_CHANGE) {
     event_string = env->change_string();
   } else {
-    CHECK(0 && "bad fs events flag");
+    UNREACHABLE("bad fs events flag");
   }
 
   Local<Value> argv[] = {
diff --git a/src/node_zlib.cc b/src/node_zlib.cc
index 3d130e8eb64859..fac116f9e6b3e2 100644
--- a/src/node_zlib.cc
+++ b/src/node_zlib.cc
@@ -313,7 +313,7 @@ class CompressionStream : public AsyncWrap, public ThreadPoolWork {
         flush != Z_FULL_FLUSH &&
         flush != Z_FINISH &&
         flush != Z_BLOCK) {
-      CHECK(0 && "Invalid flush value");
+      UNREACHABLE("Invalid flush value");
     }
 
     if (args[1]->IsNull()) {
@@ -814,7 +814,7 @@ void ZlibContext::DoThreadPoolWork() {
 
           break;
         default:
-          CHECK(0 && "invalid number of gzip magic number bytes read");
+          UNREACHABLE("invalid number of gzip magic number bytes read");
       }
 
       [[fallthrough]];
diff --git a/src/spawn_sync.cc b/src/spawn_sync.cc
index a602795e54fdca..ae4a85a42d6166 100644
--- a/src/spawn_sync.cc
+++ b/src/spawn_sync.cc
@@ -931,8 +931,7 @@ int SyncProcessRunner::ParseStdioOption(int child_fd,
     return AddStdioInheritFD(child_fd, inherit_fd);
 
   } else {
-    CHECK(0 && "invalid child stdio type");
-    return UV_EINVAL;
+    UNREACHABLE("invalid child stdio type");
   }
 }
 
diff --git a/src/string_bytes.cc b/src/string_bytes.cc
index 0e6b8b842141c5..98da55a9d71f21 100644
--- a/src/string_bytes.cc
+++ b/src/string_bytes.cc
@@ -368,8 +368,7 @@ size_t StringBytes::Write(Isolate* isolate,
       break;
 
     default:
-      CHECK(0 && "unknown encoding");
-      break;
+      UNREACHABLE("unknown encoding");
   }
 
   return nbytes;
@@ -423,8 +422,7 @@ Maybe<size_t> StringBytes::StorageSize(Isolate* isolate,
       break;
 
     default:
-      CHECK(0 && "unknown encoding");
-      break;
+      UNREACHABLE("unknown encoding");
   }
 
   return Just(data_size);
diff --git a/src/udp_wrap.cc b/src/udp_wrap.cc
index 772021ff653089..cad50fec409730 100644
--- a/src/udp_wrap.cc
+++ b/src/udp_wrap.cc
@@ -233,7 +233,7 @@ int sockaddr_for_family(int address_family,
     case AF_INET6:
       return uv_ip6_addr(address, port, reinterpret_cast<sockaddr_in6*>(addr));
     default:
-      CHECK(0 && "unexpected address family");
+      UNREACHABLE("unexpected address family");
   }
 }