diff --git a/libcxx/docs/OneRangesProposalStatus.csv b/libcxx/docs/OneRangesProposalStatus.csv
--- a/libcxx/docs/OneRangesProposalStatus.csv
+++ b/libcxx/docs/OneRangesProposalStatus.csv
@@ -61,7 +61,7 @@
 | indirectly_copyable
 | indirectly_copyable_storable",[iterator.concepts],Zoe Carver,In progress
 [common.alg.req]: pt. 2,indirectly_swappable,"| [iterator.concepts]
-| [iterator.cust.swap]",Louis Dionne,Not started
+| [iterator.cust.swap]",Zoe Carver,✅
 [common.alg.req]: pt. 3,indirectly_comparable,[projected],Louis Dionne,Not started
 [common.alg.req]: pt. 4,"| permutable
 | mergeable
diff --git a/libcxx/include/__iterator/concepts.h b/libcxx/include/__iterator/concepts.h
--- a/libcxx/include/__iterator/concepts.h
+++ b/libcxx/include/__iterator/concepts.h
@@ -249,6 +249,8 @@
   constructible_from<iter_value_t<_In>, iter_rvalue_reference_t<_In>> &&
   assignable_from<iter_value_t<_In>&, iter_rvalue_reference_t<_In>>;
 
+// Note: indirectly_swappable is located in iter_swap.h.
+
 // clang-format on
 
 #endif // !defined(_LIBCPP_HAS_NO_RANGES)
diff --git a/libcxx/include/__iterator/iter_swap.h b/libcxx/include/__iterator/iter_swap.h
--- a/libcxx/include/__iterator/iter_swap.h
+++ b/libcxx/include/__iterator/iter_swap.h
@@ -85,6 +85,16 @@
 
 } // namespace ranges
 
+template<class _I1, class _I2 = _I1>
+concept indirectly_swappable =
+  indirectly_readable<_I1> && indirectly_readable<_I2> &&
+  requires(const _I1 __i1, const _I2 __i2) {
+    ranges::iter_swap(__i1, __i1);
+    ranges::iter_swap(__i2, __i2);
+    ranges::iter_swap(__i1, __i2);
+    ranges::iter_swap(__i2, __i1);
+  };
+
 #endif // !defined(_LIBCPP_HAS_NO_RANGES)
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/iterator b/libcxx/include/iterator
--- a/libcxx/include/iterator
+++ b/libcxx/include/iterator
@@ -132,6 +132,10 @@
 template<class In, class Out>
   concept indirectly_movable_storable = see below;         // since C++20
 
+// [alg.req.ind.swap], concept indirectly_swappable
+template<class I1, class I2 = I1>
+  concept indirectly_swappable = see below;                // since C++20
+
 template<class Category, class T, class Distance = ptrdiff_t,
          class Pointer = T*, class Reference = T&>
 struct iterator                                            // deprecated in C++17
diff --git a/libcxx/test/std/iterators/iterator.requirements/alg.req.ind.swap/indirectly_swappable.compile.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/alg.req.ind.swap/indirectly_swappable.compile.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/iterators/iterator.requirements/alg.req.ind.swap/indirectly_swappable.compile.pass.cpp
@@ -0,0 +1,80 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+// UNSUPPORTED: gcc-10
+
+// template<class I1, class I2>
+// concept indirectly_swappable;
+
+#include <iterator>
+
+#include "test_macros.h"
+
+template<class T, class ValueType = T>
+struct PointerTo {
+  using value_type = ValueType;
+  T& operator*() const;
+};
+
+static_assert(std::indirectly_swappable<PointerTo<int>>);
+static_assert(std::indirectly_swappable<PointerTo<int>, PointerTo<int>>);
+
+struct B;
+
+struct A {
+  friend void iter_swap(const PointerTo<A>&, const PointerTo<A>&);
+};
+
+// Is indirectly swappable.
+struct B {
+  friend void iter_swap(const PointerTo<B>&, const PointerTo<B>&);
+  friend void iter_swap(const PointerTo<A>&, const PointerTo<B>&);
+  friend void iter_swap(const PointerTo<B>&, const PointerTo<A>&);
+};
+
+// Valid except ranges::iter_swap(i2, i1).
+struct C {
+  friend void iter_swap(const PointerTo<C>&, const PointerTo<C>&);
+  friend void iter_swap(const PointerTo<A>&, const PointerTo<C>&);
+  friend void iter_swap(const PointerTo<C>&, const PointerTo<A>&) = delete;
+};
+
+// Valid except ranges::iter_swap(i1, i2).
+struct D {
+  friend void iter_swap(const PointerTo<D>&, const PointerTo<D>&);
+  friend void iter_swap(const PointerTo<A>&, const PointerTo<D>&) = delete;
+  friend void iter_swap(const PointerTo<D>&, const PointerTo<A>&);
+};
+
+// Valid except ranges::iter_swap(i2, i2).
+struct E {
+  E operator=(const E&) = delete;
+  friend void iter_swap(const PointerTo<E>&, const PointerTo<E>&) = delete;
+  friend void iter_swap(const PointerTo<A>&, const PointerTo<E>&);
+  friend void iter_swap(const PointerTo<E>&, const PointerTo<A>&);
+};
+
+struct F {
+  friend void iter_swap(const PointerTo<F>&, const PointerTo<F>&) = delete;
+};
+
+// Valid except ranges::iter_swap(i1, i1).
+struct G {
+  friend void iter_swap(const PointerTo<G>&, const PointerTo<G>&);
+  friend void iter_swap(const PointerTo<F>&, const PointerTo<G>&);
+  friend void iter_swap(const PointerTo<G>&, const PointerTo<F>&);
+};
+
+
+static_assert( std::indirectly_swappable<PointerTo<A>, PointerTo<B>>);
+static_assert(!std::indirectly_swappable<PointerTo<A>, PointerTo<C>>);
+static_assert(!std::indirectly_swappable<PointerTo<A>, PointerTo<D>>);
+static_assert(!std::indirectly_swappable<PointerTo<A>, PointerTo<E>>);
+static_assert(!std::indirectly_swappable<PointerTo<A>, PointerTo<G>>);
diff --git a/libcxx/test/std/iterators/iterator.requirements/alg.req.ind.swap/indirectly_swappable.subsumption.compile.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/alg.req.ind.swap/indirectly_swappable.subsumption.compile.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/iterators/iterator.requirements/alg.req.ind.swap/indirectly_swappable.subsumption.compile.pass.cpp
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+// UNSUPPORTED: gcc-10
+
+// template<class I1, class I2>
+// concept indirectly_swappable;
+
+#include <iterator>
+
+#include <concepts>
+
+template<class I1, class I2>
+  requires std::indirectly_readable<I1> && std::indirectly_readable<I2>
+constexpr bool indirectly_swappable_subsumption() {
+  return false;
+}
+
+template<class I1, class I2>
+  requires std::indirectly_swappable<I1, I2>
+constexpr bool indirectly_swappable_subsumption() {
+  return true;
+}
+
+static_assert(indirectly_swappable_subsumption<int*, int*>());