diff --git a/types/defines/ratelimit.d.ts b/types/defines/ratelimit.d.ts
index a37ec6013fb..388c45bfad3 100644
--- a/types/defines/ratelimit.d.ts
+++ b/types/defines/ratelimit.d.ts
@@ -1,5 +1,11 @@
 interface RateLimitOptions {
   key: string
+  /**
+   * Amount to add to the counter for this call. Must be a positive integer;
+   * defaults to `1`. The call is allowed while the counter is below the limit,
+   * even if `delta` takes it past the limit.
+   */
+  delta?: number
 }
 
 interface RateLimitOutcome {
diff --git a/types/generated-snapshot/experimental/index.d.ts b/types/generated-snapshot/experimental/index.d.ts
index c319c9c8ea3..d264090f22a 100755
--- a/types/generated-snapshot/experimental/index.d.ts
+++ b/types/generated-snapshot/experimental/index.d.ts
@@ -16552,6 +16552,12 @@ interface JsonWebKeyWithKid extends JsonWebKey {
 }
 interface RateLimitOptions {
   key: string;
+  /**
+   * Amount to add to the counter for this call. Must be a positive integer;
+   * defaults to `1`. The call is allowed while the counter is below the limit,
+   * even if `delta` takes it past the limit.
+   */
+  delta?: number;
 }
 interface RateLimitOutcome {
   success: boolean;
diff --git a/types/generated-snapshot/experimental/index.ts b/types/generated-snapshot/experimental/index.ts
index 27f7240092a..1788008fde9 100755
--- a/types/generated-snapshot/experimental/index.ts
+++ b/types/generated-snapshot/experimental/index.ts
@@ -16462,6 +16462,12 @@ export interface JsonWebKeyWithKid extends JsonWebKey {
 }
 export interface RateLimitOptions {
   key: string;
+  /**
+   * Amount to add to the counter for this call. Must be a positive integer;
+   * defaults to `1`. The call is allowed while the counter is below the limit,
+   * even if `delta` takes it past the limit.
+   */
+  delta?: number;
 }
 export interface RateLimitOutcome {
   success: boolean;
diff --git a/types/generated-snapshot/index.d.ts b/types/generated-snapshot/index.d.ts
index fcd35c5d71e..a206da5399e 100755
--- a/types/generated-snapshot/index.d.ts
+++ b/types/generated-snapshot/index.d.ts
@@ -16191,6 +16191,12 @@ interface JsonWebKeyWithKid extends JsonWebKey {
 }
 interface RateLimitOptions {
   key: string;
+  /**
+   * Amount to add to the counter for this call. Must be a positive integer;
+   * defaults to `1`. The call is allowed while the counter is below the limit,
+   * even if `delta` takes it past the limit.
+   */
+  delta?: number;
 }
 interface RateLimitOutcome {
   success: boolean;
diff --git a/types/generated-snapshot/index.ts b/types/generated-snapshot/index.ts
index 471fddf0030..98088e9bcd1 100755
--- a/types/generated-snapshot/index.ts
+++ b/types/generated-snapshot/index.ts
@@ -16104,6 +16104,12 @@ export interface JsonWebKeyWithKid extends JsonWebKey {
 }
 export interface RateLimitOptions {
   key: string;
+  /**
+   * Amount to add to the counter for this call. Must be a positive integer;
+   * defaults to `1`. The call is allowed while the counter is below the limit,
+   * even if `delta` takes it past the limit.
+   */
+  delta?: number;
 }
 export interface RateLimitOutcome {
   success: boolean;
diff --git a/types/test/types/ratelimit.ts b/types/test/types/ratelimit.ts
new file mode 100644
index 00000000000..a72d89dbd1e
--- /dev/null
+++ b/types/test/types/ratelimit.ts
@@ -0,0 +1,17 @@
+// Copyright (c) 2026 Cloudflare, Inc.
+// Licensed under the Apache 2.0 license found in the LICENSE file or at:
+// https://opensource.org/licenses/Apache-2.0
+
+function expectType<T>(_value: T) {}
+
+declare const limiter: RateLimit;
+
+expectType<Promise<RateLimitOutcome>>(limiter.limit({ key: 'user-123' }));
+expectType<Promise<RateLimitOutcome>>(
+  limiter.limit({ key: 'user-123', delta: 5 })
+);
+
+// @ts-expect-error `delta` must be a number.
+limiter.limit({ key: 'user-123', delta: '5' });
+// @ts-expect-error `key` is required.
+limiter.limit({ delta: 5 });