diff --git a/bilby/core/utils/io.py b/bilby/core/utils/io.py
index 8299d6816..52184b3b9 100644
--- a/bilby/core/utils/io.py
+++ b/bilby/core/utils/io.py
@@ -69,6 +69,8 @@ def default(self, obj):
             return {"__series__": True, "content": obj.to_dict()}
         if isinstance(obj, np.random.Generator):
             return encode_numpy_random_generator(obj)
+        if isinstance(obj, np.random.SeedSequence):
+            return encode_numpy_seed_sequence(obj)
         if inspect.isfunction(obj):
             return {
                 "__function__": True,
@@ -162,11 +164,29 @@ def encode_numpy_random_generator(generator):
     }
 
 
+def encode_numpy_seed_sequence(seed_sequence):
+    """Encode a numpy SeedSequence to a dictionary.
+
+    Adds the key :code:`__numpy_seed_sequence__` to the dictionary to indicate
+    that the object is a numpy SeedSequence.
+
+    The :code:`state` key contains the state of the seed sequence.
+
+    .. versionadded:: 3.0.0
+    """
+    state = dict(seed_sequence.state)
+    state["spawn_key"] = list(state["spawn_key"])
+    return {
+        "__numpy_seed_sequence__": True,
+        "state": state,
+    }
+
+
 def decode_astropy_cosmology(dct):
     """Decode an astropy cosmology from a dictionary.
 
     The dictionary should have been encoded using
-    :py:func:`~bibly.core.utils.io.encode_astropy_cosmology` and should have the
+    :py:func:`~bilby.core.utils.io.encode_astropy_cosmology` and should have the
     key :code:`__cosmology__`.
 
     .. versionchange:: 2.5.0
@@ -270,6 +290,16 @@ def decode_numpy_random_generator(dct):
     return generator
 
 
+def decode_numpy_seed_sequence(dct):
+    """Decode a numpy SeedSequence from a dictionary.
+
+    .. versionadded:: 3.0.0
+    """
+    state = dict(dct["state"])
+    state["spawn_key"] = tuple(int(idx) for idx in state["spawn_key"])
+    return np.random.SeedSequence(**state)
+
+
 def load_json(filename, gzip):
     if gzip or os.path.splitext(filename)[1].lstrip(".") == "gz":
         import gzip
@@ -313,6 +343,8 @@ def decode_bilby_json(dct):
         return obj
     if dct.get("__numpy_random_generator__", False):
         return decode_numpy_random_generator(dct)
+    if dct.get("__numpy_seed_sequence__", False):
+        return decode_numpy_seed_sequence(dct)
     if dct.get("__cosmology__", False):
         return decode_astropy_cosmology(dct)
     if dct.get("__astropy_quantity__", False):
@@ -442,6 +474,8 @@ def encode_for_hdf5(key, item):
         output = item
     elif isinstance(item, np.random.Generator):
         output = encode_numpy_random_generator(item)
+    elif isinstance(item, np.random.SeedSequence):
+        output = encode_numpy_seed_sequence(item)
     elif item is None:
         output = "__none__"
     elif isinstance(item, list):
@@ -508,6 +542,8 @@ def decode_hdf5_dict(output):
         output = decode_astropy_unit(output)
     elif "__numpy_random_generator__" in output:
         output = decode_numpy_random_generator(output)
+    elif "__numpy_seed_sequence__" in output:
+        output = decode_numpy_seed_sequence(output)
     return output
 
 
diff --git a/test/core/utils_test.py b/test/core/utils_test.py
index df46d6bb3..b1dff0313 100644
--- a/test/core/utils_test.py
+++ b/test/core/utils_test.py
@@ -462,6 +462,38 @@ def test_json(self):
         b = data["rng"].random()
         self.assertEqual(a, b)
 
+    def test_hdf5_seed_sequence(self):
+        seed_sequence = np.random.SeedSequence(1234).spawn(1)[0]
+        data = {"seed_sequence": seed_sequence}
+
+        with h5py.File(self.outdir / "test_seed_sequence.h5", "w") as f:
+            bilby.core.utils.recursively_save_dict_contents_to_group(
+                f, "/", data
+            )
+
+        with h5py.File(self.outdir / "test_seed_sequence.h5", "r") as f:
+            loaded = bilby.core.utils.recursively_load_dict_contents_from_group(
+                f, "/"
+            )
+
+        self.assertIsInstance(loaded["seed_sequence"], np.random.SeedSequence)
+        self.assertEqual(loaded["seed_sequence"].state, seed_sequence.state)
+
+    def test_json_seed_sequence(self):
+        seed_sequence = np.random.SeedSequence(1234).spawn(1)[0]
+        data = {"seed_sequence": seed_sequence}
+
+        with open(self.outdir / "test_seed_sequence.json", "w") as file:
+            json.dump(data, file, indent=2, cls=bilby.core.utils.BilbyJsonEncoder)
+
+        with open(self.outdir / "test_seed_sequence.json", "r") as file:
+            loaded = json.load(
+                file, object_hook=bilby.core.utils.decode_bilby_json
+            )
+
+        self.assertIsInstance(loaded["seed_sequence"], np.random.SeedSequence)
+        self.assertEqual(loaded["seed_sequence"].state, seed_sequence.state)
+
     def test_pickle(self):
         with open(self.outdir / "test.pkl", 'wb') as file:
             dill.dump(self.data, file)