diff --git a/CHANGELOG.md b/CHANGELOG.md
index 40aa2e88..9a64b677 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,7 +14,8 @@ orchestration time, preventing retries from expiring solely because history is
 replayed later. Retry calculations also accept timezone-aware timestamps.
 Histories that recorded timeout failures based on wall-clock time can replay
 differently; drain affected instances on the previous SDK before upgrading.
-- Type discovery now recognizes `dict` / `Mapping` and `tuple` containers wrapping
+- Type discovery now recognizes `dict` / `Mapping` / `MutableMapping`,
+`tuple`, and `list` / `Sequence` / `MutableSequence` containers wrapping
 reconstructable types (such as dataclasses and `from_json()`-capable types) via
 `JsonDataConverter.can_reconstruct()`. Inbound activity and orchestrator inputs as
 well as inferred activity return types annotated with these containers are now
@@ -23,8 +24,9 @@ automatically reconstructed into typed model instances without requiring an expl
 
 > [!WARNING]
 > **Replay-breaking bug fix:** Container annotations involving `dict`, `Mapping`,
-> or `tuple` wrapping reconstructable types, including nested annotations, now
-> reconstruct orchestration inputs and inferred activity results by default.
+> `MutableMapping`, `list`, `Sequence`, `MutableSequence`, or `tuple` wrapping
+> reconstructable types, including nested annotations, now reconstruct
+> orchestration inputs and inferred activity results by default.
 > Existing instances that relied on raw dictionaries or lists can change behavior
 > or fail replay with `NonDeterminismError`.
 >
diff --git a/durabletask-azuremanaged/CHANGELOG.md b/durabletask-azuremanaged/CHANGELOG.md
index 1b327beb..2f3ce7a9 100644
--- a/durabletask-azuremanaged/CHANGELOG.md
+++ b/durabletask-azuremanaged/CHANGELOG.md
@@ -14,10 +14,11 @@ FIXED
 wall-clock time. See the [core upgrade guidance](../CHANGELOG.md#unreleased)
 for histories that recorded timeout failures under the previous behavior.
 - With the corresponding core `durabletask` SDK update, type discovery now recognizes
-`dict`, `Mapping`, and `tuple` container annotations wrapping reconstructable types,
-automatically reconstructing recorded inputs and inferred activity results into typed model
-instances. See the [core upgrade warning](../CHANGELOG.md#unreleased) for replay-breaking
-guidance and dependency pinning recommendations.
+`dict`, `Mapping`, `MutableMapping`, `list`, `Sequence`, `MutableSequence`, and `tuple`
+container annotations wrapping reconstructable types, automatically reconstructing recorded
+inputs and inferred activity results into typed model instances. See the
+[core upgrade warning](../CHANGELOG.md#unreleased) for replay-breaking guidance and
+dependency pinning recommendations.
 
 ## v1.13.1
 
diff --git a/durabletask/serialization.py b/durabletask/serialization.py
index 7f10cae8..9c0bd0a0 100644
--- a/durabletask/serialization.py
+++ b/durabletask/serialization.py
@@ -42,7 +42,7 @@
 import types
 import typing
 from abc import ABC, abstractmethod
-from collections.abc import Iterable, Mapping, Sequence
+from collections.abc import Iterable, Mapping, MutableMapping, MutableSequence, Sequence
 from collections.abc import Set as AbstractSet
 from types import SimpleNamespace
 from typing import Any, cast
@@ -268,9 +268,9 @@ def _can_reconstruct(converter: DataConverter, target_type: Any) -> bool:
     """:class:`JsonDataConverter`'s reconstruction policy.
 
     Recognizes dataclasses and ``from_json()``-capable types, plus ``Optional``,
-    ``list`` / ``Sequence``, ``dict`` / ``Mapping``, and ``tuple`` hints wrapping
-    them; builtins and unknown annotations are excluded. When set support is
-    enabled on the converter (via ``enable_generic_sets=True``), ``set`` /
+    ``list`` / ``Sequence`` / ``MutableSequence``, ``dict`` / ``Mapping`` /
+    ``MutableMapping``, and ``tuple`` hints wrapping them; builtins and unknown
+    annotations are excluded. When set support is enabled on the converter (via ``enable_generic_sets=True``), ``set`` /
     ``frozenset`` / ``Set`` containers with supported element types are also
     recognized. Recurses through ``converter.can_reconstruct`` (not itself) so a
     :class:`JsonDataConverter` subclass that overrides ``can_reconstruct``
@@ -283,7 +283,7 @@ def _can_reconstruct(converter: DataConverter, target_type: Any) -> bool:
             return any(
                 converter.can_reconstruct(a) for a in args if a is not type(None)
             )
-        if origin in (list, Sequence):
+        if origin in (list, Sequence, MutableSequence):
             return any(converter.can_reconstruct(a) for a in args)
         if origin in (set, frozenset, AbstractSet, typing.AbstractSet):
             if not getattr(converter, "enable_generic_sets", False):
@@ -291,7 +291,7 @@ def _can_reconstruct(converter: DataConverter, target_type: Any) -> bool:
             if not args:
                 return True
             return _is_supported_set_element(converter, args[0])
-        if origin in (dict, Mapping):
+        if origin in (dict, Mapping, MutableMapping):
             return len(args) == 2 and converter.can_reconstruct(args[1])
         if origin is tuple:
             if not args:
@@ -611,7 +611,7 @@ def _coerce_generic(value: Any, expected_type: Any, origin: Any,
         if len(non_none) == 1:
             return _coerce_to_type(value, non_none[0], converter)
         return value
-    if origin in (list, Sequence) and isinstance(value, list):
+    if origin in (list, Sequence, MutableSequence) and isinstance(value, list):
         elem_type = args[0] if args else None
         return [_coerce_to_type(item, elem_type, converter) for item in cast(list[Any], value)]
     if origin in (set, frozenset, AbstractSet, typing.AbstractSet) and isinstance(
@@ -627,7 +627,7 @@ def _coerce_generic(value: Any, expected_type: Any, origin: Any,
         if origin is frozenset:
             return frozenset(coerced)
         return set(coerced)
-    if origin in (dict, Mapping) and isinstance(value, dict):
+    if origin in (dict, Mapping, MutableMapping) and isinstance(value, dict):
         # JSON object keys are always strings, so only the values can carry a
         # reconstructable type. Keys are passed through unchanged.
         mapping = cast("dict[Any, Any]", value)
diff --git a/tests/durabletask/test_data_converter_roundtrip.py b/tests/durabletask/test_data_converter_roundtrip.py
index 804f81bf..aab0ab59 100644
--- a/tests/durabletask/test_data_converter_roundtrip.py
+++ b/tests/durabletask/test_data_converter_roundtrip.py
@@ -19,6 +19,7 @@
 
 from __future__ import annotations
 
+from collections.abc import MutableMapping, MutableSequence
 import enum
 import typing
 from dataclasses import dataclass, field
@@ -371,12 +372,28 @@ def test_list_of_dataclasses(conv):
     assert result == value
 
 
+def test_mutable_sequence_of_dataclasses(conv):
+    value = [Address("a", "b"), Address("c", "d")]
+    result = _round_trip(conv, value, MutableSequence[Address])
+    assert isinstance(result, list)
+    assert len(result) == 2
+    assert all(isinstance(item, Address) for item in result)
+    assert result == value
+
+
 def test_dict_of_dataclasses(conv):
     value = {"home": Address("a", "b")}
     result = _round_trip(conv, value, dict[str, Address])
     assert isinstance(result["home"], Address)
 
 
+def test_mutable_mapping_of_dataclasses(conv):
+    value = {"home": Address("a", "b")}
+    result = _round_trip(conv, value, MutableMapping[str, Address])
+    assert isinstance(result["home"], Address)
+    assert result == value
+
+
 def test_dict_of_optional_dataclasses(conv):
     value = {"a": Address("x", "y"), "b": None}
     result = _round_trip(conv, value, dict[str, typing.Optional[Address]])
diff --git a/tests/durabletask/test_type_discovery.py b/tests/durabletask/test_type_discovery.py
index 07fbe8f6..90e2640b 100644
--- a/tests/durabletask/test_type_discovery.py
+++ b/tests/durabletask/test_type_discovery.py
@@ -6,7 +6,7 @@
 import inspect
 import json
 import logging
-from collections.abc import Mapping
+from collections.abc import Mapping, MutableMapping, MutableSequence
 from dataclasses import dataclass
 from typing import Any, Optional, get_origin
 from unittest.mock import patch
@@ -69,14 +69,18 @@ def test_optional_dataclass_is_reconstructable(self):
 
     def test_list_of_dataclass_is_reconstructable(self):
         assert self.conv.can_reconstruct(list[Order]) is True
+        assert self.conv.can_reconstruct(MutableSequence[Order]) is True
 
     def test_list_of_builtin_is_not_reconstructable(self):
         assert self.conv.can_reconstruct(list[int]) is False
+        assert self.conv.can_reconstruct(MutableSequence[int]) is False
 
     def test_dict_and_mapping_of_dataclass_is_reconstructable(self):
         assert self.conv.can_reconstruct(dict[str, Order]) is True
         assert self.conv.can_reconstruct(Mapping[str, Order]) is True
+        assert self.conv.can_reconstruct(MutableMapping[str, Order]) is True
         assert self.conv.can_reconstruct(dict[str, int]) is False
+        assert self.conv.can_reconstruct(MutableMapping[str, int]) is False
 
     def test_tuple_of_dataclass_is_reconstructable(self):
         assert self.conv.can_reconstruct(tuple[Order, ...]) is True
@@ -110,11 +114,13 @@ def can_reconstruct(self, target_type: Any) -> bool:
         # The base Optional/list recursion goes through ``self``, so the override
         # is consulted for the element type.
         assert conv.can_reconstruct(list[Widget]) is True
+        assert conv.can_reconstruct(MutableSequence[Widget]) is True
         assert conv.can_reconstruct(Optional[Widget]) is True
         # Builtins remain excluded.
         assert conv.can_reconstruct(int) is False
         # The override is also consulted for elements inside dict and tuple hints.
         assert conv.can_reconstruct(dict[str, Widget]) is True
+        assert conv.can_reconstruct(MutableMapping[str, Widget]) is True
         assert conv.can_reconstruct(tuple[Widget, ...]) is True
         assert conv.can_reconstruct(tuple[Widget, int]) is True
 
@@ -515,6 +521,47 @@ def handle(ctx: task.ActivityContext, orders: tuple[Order, ...]):
     assert json.loads(result) == 2
 
 
+def test_activity_input_coerced_for_mutable_mapping_of_dataclass():
+    seen: dict[str, Any] = {}
+
+    def handle(ctx: task.ActivityContext, orders: MutableMapping[str, Order]):
+        seen["orders"] = orders
+        return sum(o.quantity for o in orders.values())
+
+    executor, name = _activity_executor(handle)
+    payload = json.dumps({"o1": {"item": "widget", "quantity": 3}, "o2": {"item": "gadget", "quantity": 7}})
+    result = executor.execute("orch1", name, 1, payload)
+
+    orders = seen["orders"]
+    assert isinstance(orders, MutableMapping)
+    assert isinstance(orders["o1"], Order)
+    assert isinstance(orders["o2"], Order)
+    assert orders["o1"].item == "widget"
+    assert orders["o2"].quantity == 7
+    assert json.loads(result) == 10
+
+
+def test_activity_input_coerced_for_mutable_sequence_of_dataclass():
+    seen: dict[str, Any] = {}
+
+    def handle(ctx: task.ActivityContext, orders: MutableSequence[Order]):
+        seen["orders"] = orders
+        return len(orders)
+
+    executor, name = _activity_executor(handle)
+    payload = json.dumps([{"item": "widget", "quantity": 3}, {"item": "gadget", "quantity": 7}])
+    result = executor.execute("orch1", name, 1, payload)
+
+    orders = seen["orders"]
+    assert isinstance(orders, MutableSequence)
+    assert len(orders) == 2
+    assert isinstance(orders[0], Order)
+    assert isinstance(orders[1], Order)
+    assert orders[0].item == "widget"
+    assert orders[1].quantity == 7
+    assert json.loads(result) == 2
+
+
 def test_activity_builtin_input_unchanged():
     seen: dict[str, Any] = {}