diff --git a/net/dcsctp/common/BUILD.gn b/net/dcsctp/common/BUILD.gn
index 6e99cdcef4..591fa44207 100644
--- a/net/dcsctp/common/BUILD.gn
+++ b/net/dcsctp/common/BUILD.gn
@@ -21,11 +21,6 @@ rtc_source_set("math") {
   sources = [ "math.h" ]
 }
 
-rtc_source_set("pair_hash") {
-  deps = []
-  sources = [ "pair_hash.h" ]
-}
-
 rtc_source_set("sequence_numbers") {
   deps = [ ":internal_types" ]
   sources = [ "sequence_numbers.h" ]
@@ -44,7 +39,6 @@ if (rtc_include_tests) {
     defines = []
     deps = [
       ":math",
-      ":pair_hash",
       ":sequence_numbers",
       ":str_join",
       "../../../api:array_view",
@@ -55,7 +49,6 @@ if (rtc_include_tests) {
     ]
     sources = [
       "math_test.cc",
-      "pair_hash_test.cc",
       "sequence_numbers_test.cc",
       "str_join_test.cc",
     ]
diff --git a/net/dcsctp/common/internal_types.h b/net/dcsctp/common/internal_types.h
index b651d45d91..3bbc05e445 100644
--- a/net/dcsctp/common/internal_types.h
+++ b/net/dcsctp/common/internal_types.h
@@ -38,13 +38,5 @@ using VerificationTag = StrongAlias<class VerificationTagTag, uint32_t>;
 // Tie Tag, used as a nonce when connecting.
 using TieTag = StrongAlias<class TieTagTag, uint64_t>;
 
-// Hasher for separated ordered/unordered stream identifiers.
-struct UnorderedStreamHash {
-  size_t operator()(const std::pair<IsUnordered, StreamID>& p) const {
-    return std::hash<IsUnordered::UnderlyingType>{}(*p.first) ^
-           (std::hash<StreamID::UnderlyingType>{}(*p.second) << 1);
-  }
-};
-
 }  // namespace dcsctp
 #endif  // NET_DCSCTP_COMMON_INTERNAL_TYPES_H_
diff --git a/net/dcsctp/common/pair_hash.h b/net/dcsctp/common/pair_hash.h
deleted file mode 100644
index 62af8b4221..0000000000
--- a/net/dcsctp/common/pair_hash.h
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- *  Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-#ifndef NET_DCSCTP_COMMON_PAIR_HASH_H_
-#define NET_DCSCTP_COMMON_PAIR_HASH_H_
-
-#include <stddef.h>
-
-#include <functional>
-#include <utility>
-
-namespace dcsctp {
-
-// A custom hash function for std::pair, to be able to be used as key in a
-// std::unordered_map. If absl::flat_hash_map would ever be used, this is
-// unnecessary as it already has a hash function for std::pair.
-struct PairHash {
-  template <class T1, class T2>
-  size_t operator()(const std::pair<T1, T2>& p) const {
-    return (3 * std::hash<T1>{}(p.first)) ^ std::hash<T2>{}(p.second);
-  }
-};
-}  // namespace dcsctp
-
-#endif  // NET_DCSCTP_COMMON_PAIR_HASH_H_
diff --git a/net/dcsctp/common/pair_hash_test.cc b/net/dcsctp/common/pair_hash_test.cc
deleted file mode 100644
index bcc3ec86c0..0000000000
--- a/net/dcsctp/common/pair_hash_test.cc
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- *  Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-#include "net/dcsctp/common/pair_hash.h"
-
-#include <unordered_map>
-#include <unordered_set>
-
-#include "test/gmock.h"
-
-namespace dcsctp {
-namespace {
-
-TEST(PairHashTest, CanInsertIntoSet) {
-  using MyPair = std::pair<int, int>;
-
-  std::unordered_set<MyPair, PairHash> pairs;
-
-  pairs.insert({1, 2});
-  pairs.insert({3, 4});
-
-  EXPECT_NE(pairs.find({1, 2}), pairs.end());
-  EXPECT_NE(pairs.find({3, 4}), pairs.end());
-  EXPECT_EQ(pairs.find({1, 3}), pairs.end());
-  EXPECT_EQ(pairs.find({3, 3}), pairs.end());
-}
-
-TEST(PairHashTest, CanInsertIntoMap) {
-  using MyPair = std::pair<int, int>;
-
-  std::unordered_map<MyPair, int, PairHash> pairs;
-
-  pairs[{1, 2}] = 99;
-  pairs[{3, 4}] = 100;
-
-  EXPECT_EQ((pairs[{1, 2}]), 99);
-  EXPECT_EQ((pairs[{3, 4}]), 100);
-  EXPECT_EQ(pairs.find({1, 3}), pairs.end());
-  EXPECT_EQ(pairs.find({3, 3}), pairs.end());
-}
-}  // namespace
-}  // namespace dcsctp
diff --git a/net/dcsctp/public/BUILD.gn b/net/dcsctp/public/BUILD.gn
index ced94de151..d92207be48 100644
--- a/net/dcsctp/public/BUILD.gn
+++ b/net/dcsctp/public/BUILD.gn
@@ -92,6 +92,7 @@ if (rtc_include_tests) {
       "../../../rtc_base:checks",
       "../../../rtc_base:gunit_helpers",
       "../../../rtc_base:rtc_base_approved",
+      "../../../rtc_base/containers:flat_map",
       "../../../test:test_support",
     ]
     sources = [
diff --git a/net/dcsctp/public/strong_alias.h b/net/dcsctp/public/strong_alias.h
index 7aea362c57..fd6302d2ed 100644
--- a/net/dcsctp/public/strong_alias.h
+++ b/net/dcsctp/public/strong_alias.h
@@ -67,15 +67,6 @@ class StrongAlias {
     return value_ >= other.value_;
   }
 
-  // Hasher to use in std::unordered_map, std::unordered_set, etc.
-  struct Hasher {
-    using argument_type = StrongAlias;
-    using result_type = std::size_t;
-    result_type operator()(const argument_type& id) const {
-      return std::hash<UnderlyingType>()(id.value());
-    }
-  };
-
  protected:
   UnderlyingType value_;
 };
diff --git a/net/dcsctp/public/strong_alias_test.cc b/net/dcsctp/public/strong_alias_test.cc
index cacb49dcb4..63aa60995c 100644
--- a/net/dcsctp/public/strong_alias_test.cc
+++ b/net/dcsctp/public/strong_alias_test.cc
@@ -15,9 +15,9 @@
 #include <memory>
 #include <string>
 #include <type_traits>
-#include <unordered_map>
 #include <utility>
 
+#include "rtc_base/containers/flat_map.h"
 #include "rtc_base/gunit.h"
 #include "test/gmock.h"
 
@@ -280,9 +280,9 @@ TEST(StrongAliasTest, CanWrapComplexStructures) {
   // namespace. So we can't print ComplexAlias.
 }
 
-TYPED_TEST(StrongAliasTest, CanBeKeysInStdUnorderedMap) {
+TYPED_TEST(StrongAliasTest, CanBeKeysInFlatMap) {
   using FooAlias = StrongAlias<class FooTag, TypeParam>;
-  std::unordered_map<FooAlias, std::string, typename FooAlias::Hasher> map;
+  webrtc::flat_map<FooAlias, std::string> map;
 
   FooAlias k1(GetExampleValue<TypeParam>(0));
   FooAlias k2(GetExampleValue<TypeParam>(1));
diff --git a/net/dcsctp/rx/traditional_reassembly_streams.cc b/net/dcsctp/rx/traditional_reassembly_streams.cc
index 7cec1150d5..4108d37236 100644
--- a/net/dcsctp/rx/traditional_reassembly_streams.cc
+++ b/net/dcsctp/rx/traditional_reassembly_streams.cc
@@ -16,7 +16,6 @@
 #include <iterator>
 #include <map>
 #include <numeric>
-#include <unordered_map>
 #include <utility>
 #include <vector>
 
diff --git a/net/dcsctp/rx/traditional_reassembly_streams.h b/net/dcsctp/rx/traditional_reassembly_streams.h
index 12d1d933a4..d7ae2dd1b3 100644
--- a/net/dcsctp/rx/traditional_reassembly_streams.h
+++ b/net/dcsctp/rx/traditional_reassembly_streams.h
@@ -14,7 +14,6 @@
 
 #include <map>
 #include <string>
-#include <unordered_map>
 
 #include "absl/strings/string_view.h"
 #include "api/array_view.h"
@@ -108,10 +107,8 @@ class TraditionalReassemblyStreams : public ReassemblyStreams {
   const OnAssembledMessage on_assembled_message_;
 
   // All unordered and ordered streams, managing not-yet-assembled data.
-  std::unordered_map<StreamID, UnorderedStream, StreamID::Hasher>
-      unordered_streams_;
-  std::unordered_map<StreamID, OrderedStream, StreamID::Hasher>
-      ordered_streams_;
+  std::map<StreamID, UnorderedStream> unordered_streams_;
+  std::map<StreamID, OrderedStream> ordered_streams_;
 };
 
 }  // namespace dcsctp
diff --git a/net/dcsctp/socket/BUILD.gn b/net/dcsctp/socket/BUILD.gn
index 805c6779b9..895292001c 100644
--- a/net/dcsctp/socket/BUILD.gn
+++ b/net/dcsctp/socket/BUILD.gn
@@ -52,6 +52,7 @@ rtc_library("stream_reset_handler") {
     "../../../rtc_base",
     "../../../rtc_base:checks",
     "../../../rtc_base:rtc_base_approved",
+    "../../../rtc_base/containers:flat_set",
     "../common:internal_types",
     "../common:str_join",
     "../packet:chunk",
diff --git a/net/dcsctp/socket/stream_reset_handler.cc b/net/dcsctp/socket/stream_reset_handler.cc
index a1f57e6b2b..40cb8f6166 100644
--- a/net/dcsctp/socket/stream_reset_handler.cc
+++ b/net/dcsctp/socket/stream_reset_handler.cc
@@ -11,7 +11,6 @@
 
 #include <cstdint>
 #include <memory>
-#include <unordered_set>
 #include <utility>
 #include <vector>
 
diff --git a/net/dcsctp/socket/stream_reset_handler.h b/net/dcsctp/socket/stream_reset_handler.h
index fe01ac7c43..7f72889356 100644
--- a/net/dcsctp/socket/stream_reset_handler.h
+++ b/net/dcsctp/socket/stream_reset_handler.h
@@ -13,7 +13,6 @@
 #include <cstdint>
 #include <memory>
 #include <string>
-#include <unordered_set>
 #include <utility>
 #include <vector>
 
@@ -33,6 +32,7 @@
 #include "net/dcsctp/socket/context.h"
 #include "net/dcsctp/timer/timer.h"
 #include "net/dcsctp/tx/retransmission_queue.h"
+#include "rtc_base/containers/flat_set.h"
 
 namespace dcsctp {
 
@@ -207,7 +207,7 @@ class StreamResetHandler {
 
   // Outgoing streams that have been requested to be reset, but hasn't yet
   // been included in an outgoing request.
-  std::unordered_set<StreamID, StreamID::Hasher> streams_to_reset_;
+  webrtc::flat_set<StreamID> streams_to_reset_;
 
   // The next sequence number for outgoing stream requests.
   ReconfigRequestSN next_outgoing_req_seq_nbr_;
diff --git a/net/dcsctp/timer/BUILD.gn b/net/dcsctp/timer/BUILD.gn
index a0ba5b030e..286bbe9cf5 100644
--- a/net/dcsctp/timer/BUILD.gn
+++ b/net/dcsctp/timer/BUILD.gn
@@ -14,6 +14,8 @@ rtc_library("timer") {
     "../../../rtc_base",
     "../../../rtc_base:checks",
     "../../../rtc_base:rtc_base_approved",
+    "../../../rtc_base/containers:flat_map",
+    "../../../rtc_base/containers:flat_set",
     "../public:socket",
     "../public:strong_alias",
     "../public:types",
diff --git a/net/dcsctp/timer/fake_timeout.h b/net/dcsctp/timer/fake_timeout.h
index 927e6b2808..f2bf10325e 100644
--- a/net/dcsctp/timer/fake_timeout.h
+++ b/net/dcsctp/timer/fake_timeout.h
@@ -14,13 +14,13 @@
 #include <functional>
 #include <limits>
 #include <memory>
-#include <unordered_set>
 #include <utility>
 #include <vector>
 
 #include "absl/types/optional.h"
 #include "net/dcsctp/public/timeout.h"
 #include "rtc_base/checks.h"
+#include "rtc_base/containers/flat_set.h"
 
 namespace dcsctp {
 
@@ -93,7 +93,7 @@ class FakeTimeoutManager {
 
  private:
   const std::function<TimeMs()> get_time_;
-  std::unordered_set<FakeTimeout*> timers_;
+  webrtc::flat_set<FakeTimeout*> timers_;
 };
 
 }  // namespace dcsctp
diff --git a/net/dcsctp/timer/timer.cc b/net/dcsctp/timer/timer.cc
index 593d639fa7..8f64533d47 100644
--- a/net/dcsctp/timer/timer.cc
+++ b/net/dcsctp/timer/timer.cc
@@ -13,7 +13,6 @@
 #include <cstdint>
 #include <limits>
 #include <memory>
-#include <unordered_map>
 #include <utility>
 
 #include "absl/memory/memory.h"
diff --git a/net/dcsctp/timer/timer.h b/net/dcsctp/timer/timer.h
index bf923ea4ca..2010b23a77 100644
--- a/net/dcsctp/timer/timer.h
+++ b/net/dcsctp/timer/timer.h
@@ -14,9 +14,9 @@
 
 #include <algorithm>
 #include <functional>
+#include <map>
 #include <memory>
 #include <string>
-#include <unordered_map>
 #include <utility>
 
 #include "absl/strings/string_view.h"
@@ -176,7 +176,7 @@ class TimerManager {
 
  private:
   const std::function<std::unique_ptr<Timeout>()> create_timeout_;
-  std::unordered_map<TimerID, Timer*, TimerID::Hasher> timers_;
+  std::map<TimerID, Timer*> timers_;
   TimerID next_id_ = TimerID(0);
 };
 
diff --git a/net/dcsctp/tx/BUILD.gn b/net/dcsctp/tx/BUILD.gn
index 2f0b27afc6..50e424cc25 100644
--- a/net/dcsctp/tx/BUILD.gn
+++ b/net/dcsctp/tx/BUILD.gn
@@ -26,7 +26,6 @@ rtc_library("rr_send_queue") {
     "../../../api:array_view",
     "../../../rtc_base:checks",
     "../../../rtc_base:rtc_base_approved",
-    "../common:pair_hash",
     "../packet:data",
     "../public:socket",
     "../public:types",
@@ -76,7 +75,6 @@ rtc_library("retransmission_queue") {
     "../../../rtc_base:checks",
     "../../../rtc_base:rtc_base_approved",
     "../common:math",
-    "../common:pair_hash",
     "../common:sequence_numbers",
     "../common:str_join",
     "../packet:chunk",
diff --git a/net/dcsctp/tx/retransmission_queue.cc b/net/dcsctp/tx/retransmission_queue.cc
index d73616eaf0..0156a56c96 100644
--- a/net/dcsctp/tx/retransmission_queue.cc
+++ b/net/dcsctp/tx/retransmission_queue.cc
@@ -16,7 +16,6 @@
 #include <map>
 #include <set>
 #include <string>
-#include <unordered_map>
 #include <utility>
 #include <vector>
 
@@ -25,7 +24,6 @@
 #include "absl/types/optional.h"
 #include "api/array_view.h"
 #include "net/dcsctp/common/math.h"
-#include "net/dcsctp/common/pair_hash.h"
 #include "net/dcsctp/common/sequence_numbers.h"
 #include "net/dcsctp/common/str_join.h"
 #include "net/dcsctp/packet/chunk/data_chunk.h"
@@ -846,8 +844,7 @@ size_t RetransmissionQueue::max_bytes_to_send() const {
 }
 
 ForwardTsnChunk RetransmissionQueue::CreateForwardTsn() const {
-  std::unordered_map<StreamID, SSN, StreamID::Hasher>
-      skipped_per_ordered_stream;
+  std::map<StreamID, SSN> skipped_per_ordered_stream;
   UnwrappedTSN new_cumulative_ack = last_cumulative_tsn_ack_;
 
   for (const auto& elem : outstanding_data_) {
@@ -873,8 +870,7 @@ ForwardTsnChunk RetransmissionQueue::CreateForwardTsn() const {
 }
 
 IForwardTsnChunk RetransmissionQueue::CreateIForwardTsn() const {
-  std::unordered_map<std::pair<IsUnordered, StreamID>, MID, UnorderedStreamHash>
-      skipped_per_stream;
+  std::map<std::pair<IsUnordered, StreamID>, MID> skipped_per_stream;
   UnwrappedTSN new_cumulative_ack = last_cumulative_tsn_ack_;
 
   for (const auto& elem : outstanding_data_) {
diff --git a/net/dcsctp/tx/rr_send_queue.h b/net/dcsctp/tx/rr_send_queue.h
index 3ec45af17d..ed077cdef7 100644
--- a/net/dcsctp/tx/rr_send_queue.h
+++ b/net/dcsctp/tx/rr_send_queue.h
@@ -20,7 +20,6 @@
 #include "absl/strings/string_view.h"
 #include "absl/types/optional.h"
 #include "api/array_view.h"
-#include "net/dcsctp/common/pair_hash.h"
 #include "net/dcsctp/public/dcsctp_message.h"
 #include "net/dcsctp/public/dcsctp_socket.h"
 #include "net/dcsctp/public/types.h"