diff --git a/s2/debug_disabled.go b/s2/debug_disabled.go
new file mode 100644
index 00000000..c722e8d6
--- /dev/null
+++ b/s2/debug_disabled.go
@@ -0,0 +1,22 @@
+// Copyright 2025 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !debug
+
+package s2
+
+// dcheck is a no-op in non-debug builds.
+func dcheck(condition bool, message string) {
+	// no-op
+}
diff --git a/s2/debug_enabled.go b/s2/debug_enabled.go
new file mode 100644
index 00000000..1d9cbef7
--- /dev/null
+++ b/s2/debug_enabled.go
@@ -0,0 +1,35 @@
+// Copyright 2025 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// To use these, you must set the build tag with the -tags flag as:
+//    go build -tags debug
+
+//go:build debug
+
+package s2
+
+// dcheck is a custom debug check function.
+func dcheck(condition bool, message string) {
+	if !condition {
+		panic("dcheck failed: " + message)
+	}
+}
+
+// TODO(rsned): Also create equivalents for
+// ABSL_DCHECK_EQ
+// ABSL_DCHECK_GE
+// ABSL_DCHECK_GT
+// ABSL_DCHECK_LE
+// ABSL_DCHECK_LT
+// ABSL_DCHECK_NE