diff --git a/builtin/builtin.mbti b/builtin/builtin.mbti
index f02d3c54f..5a6759c75 100644
--- a/builtin/builtin.mbti
+++ b/builtin/builtin.mbti
@@ -236,6 +236,8 @@ impl Iter {
   head[A](Self[A]) -> A?
   intersperse[A](Self[A], A) -> Self[A]
   iter[T](Self[T]) -> Self[T]
+  iter2[K, V](Self[(K, V)]) -> Iter2[K, V]
+  iteri[T](Self[T], offset~ : Int = ..) -> Iter2[Int, T]
   join(Self[String], String) -> String
   just_run[T](Self[T], (T) -> IterResult) -> Unit
   last[A](Self[A]) -> A?
diff --git a/builtin/iter.mbt b/builtin/iter.mbt
index b8cad980b..c2aa57c68 100644
--- a/builtin/iter.mbt
+++ b/builtin/iter.mbt
@@ -968,3 +968,23 @@ pub fn Iter::minimum[T : Compare](self : Iter[T]) -> T? {
   }
   res
 }
+
+///|
+/// Returns an iterator that iterates over the index and the element of the iterator.
+pub fn Iter::iteri[T](self : Iter[T], offset~ : Int = 0) -> Iter2[Int, T] {
+  fn {
+    yield_ => {
+      let mut value = offset - 1
+      self.run(fn(i) {
+        value += 1
+        yield_(value, i)
+      })
+    }
+  }
+}
+
+///|
+/// Returns an iterator that iterates over the key value pair.
+pub fn Iter::iter2[K, V](self : Iter[(K, V)]) -> Iter2[K, V] {
+  fn { yield_ => self.run(fn { (k, v) => yield_(k, v) }) }
+}
diff --git a/builtin/iter_test.mbt b/builtin/iter_test.mbt
index f55a312da..53408c239 100644
--- a/builtin/iter_test.mbt
+++ b/builtin/iter_test.mbt
@@ -748,3 +748,31 @@ test "Float::until negative step" {
   let result = 10.0.until(0.0, step=-2.0).collect()
   inspect!(result, content="[10, 8, 6, 4, 2]")
 }
+
+///|
+test "iteri" {
+  let iter = [].iter()
+  for _, _ in iter.iteri() {
+    assert_true!(false)
+  }
+  let iter = [0, 1, 2].iter()
+  for i, x in iter.iteri() {
+    assert_eq!(i, x)
+  }
+  let iter = [0, 1, 2].iter()
+  for i, x in iter.iteri(offset=10) {
+    assert_eq!(i, x + 10)
+  }
+}
+
+///|
+test "iter2" {
+  let iter = [].iter()
+  for _, _ in iter.iter2() {
+    assert_true!(false)
+  }
+  let iter = [(0, 1), (2, 3), (4, 5)].iter()
+  for k, v in iter.iter2() {
+    assert_eq!(k + 1, v)
+  }
+}