diff --git a/bindings/nodejs/lib/types/block/output/unlock-condition.ts b/bindings/nodejs/lib/types/block/output/unlock-condition.ts
index 0f70f93642..f03daf4292 100644
--- a/bindings/nodejs/lib/types/block/output/unlock-condition.ts
+++ b/bindings/nodejs/lib/types/block/output/unlock-condition.ts
@@ -156,8 +156,8 @@ class TimelockUnlockCondition extends UnlockCondition {
 }
 
 /**
- * Defines an expiration slot index. Before the slot index is reached, only the Address defined in the Address
- * Unlock Condition is allowed to unlock the output. Afterward, only the Return Address can unlock it.
+ * Defines a slot index until which only the Address defined in the Address Unlock Condition is allowed to unlock the output.
+ * After the slot index is reached/passed, only the Return Address can unlock it.
  */
 class ExpirationUnlockCondition extends UnlockCondition {
     /**
@@ -168,8 +168,7 @@ class ExpirationUnlockCondition extends UnlockCondition {
     })
     readonly returnAddress: Address;
     /**
-     * Before this slot index, the condition is allowed to unlock the output,
-     * after that only the address defined in return address.
+     * Before this slot index, the Address Unlock Condition is allowed to unlock the output, after that only the address defined in Return Address can.
      */
     readonly slotIndex: SlotIndex;
 
diff --git a/bindings/python/examples/client/build_basic.py b/bindings/python/examples/client/build_basic.py
index 5ce0101ed5..455ec49084 100644
--- a/bindings/python/examples/client/build_basic.py
+++ b/bindings/python/examples/client/build_basic.py
@@ -62,7 +62,7 @@
         address_unlock_condition,
         ExpirationUnlockCondition(
             return_address=Ed25519Address(hex_address),
-            unix_time=1
+            slot_index=1
         )
     ],
     amount=1000000,
diff --git a/bindings/python/iota_sdk/types/unlock_condition.py b/bindings/python/iota_sdk/types/unlock_condition.py
index 269383255a..f45f102625 100644
--- a/bindings/python/iota_sdk/types/unlock_condition.py
+++ b/bindings/python/iota_sdk/types/unlock_condition.py
@@ -6,7 +6,7 @@
 from typing import Dict, List, TypeAlias, Union, Any
 from dataclasses_json import config
 from iota_sdk.types.address import Address, AccountAddress
-from iota_sdk.types.common import json
+from iota_sdk.types.common import json, SlotIndex
 from iota_sdk.types.address import deserialize_address
 
 
@@ -71,11 +71,11 @@ class StorageDepositReturnUnlockCondition:
 @json
 @dataclass
 class TimelockUnlockCondition:
-    """A timelock unlock condition.
+    """Defines a slot index until which the output can not be unlocked.
     Args:
-        unix_time: The Unix timestamp marking the end of the timelock.
+        slot_index: Slot index that defines when the output can be consumed.
     """
-    unix_time: int
+    slot_index: SlotIndex
     type: int = field(
         default_factory=lambda: int(
             UnlockConditionType.Timelock),
@@ -85,12 +85,13 @@ class TimelockUnlockCondition:
 @json
 @dataclass
 class ExpirationUnlockCondition:
-    """An expiration unlock condition.
+    """Defines a slot index until which only the Address defined in the Address Unlock Condition is allowed to unlock the output. After the slot index is reached/passed, only the Return Address can unlock it.
     Args:
-        unix_time: Unix timestamp marking the expiration of the claim.
+        slot_index: Before this slot index, Address Unlock Condition is allowed to unlock the output,
+                    after that only the address defined in Return Address.
         return_address: The return address if the output was not claimed in time.
     """
-    unix_time: int
+    slot_index: SlotIndex
     return_address: Address = field(
         metadata=config(
             decoder=deserialize_address
diff --git a/bindings/python/tests/test_block.py b/bindings/python/tests/test_block.py
index c37a59580c..a02c54279d 100644
--- a/bindings/python/tests/test_block.py
+++ b/bindings/python/tests/test_block.py
@@ -174,12 +174,12 @@ def test_basic_block_with_tx_payload_all_output_types():
                                                                                                                                                                                                                                     "type": 0, "address": {
                                                                                                                                                                                                                                         "type": 0, "pubKeyHash": "0x7ffec9e1233204d9c6dce6812b1539ee96af691ca2e4d9065daa85907d33e5d3"}}, {
                                                                                                                                                                                                                                             "type": 3, "returnAddress": {
-                                                                                                                                                                                                                                                "type": 0, "pubKeyHash": "0x7ffec9e1233204d9c6dce6812b1539ee96af691ca2e4d9065daa85907d33e5d3"}, "unixTime": 1}]}, {
+                                                                                                                                                                                                                                                "type": 0, "pubKeyHash": "0x7ffec9e1233204d9c6dce6812b1539ee96af691ca2e4d9065daa85907d33e5d3"}, "slotIndex": 1}]}, {
                                                                                                                                                                                                                                                     "type": 3, "amount": "1000000", "unlockConditions": [
                                                                                                                                                                                                                                                         {
                                                                                                                                                                                                                                                             "type": 0, "address": {
                                                                                                                                                                                                                                                                 "type": 0, "pubKeyHash": "0x7ffec9e1233204d9c6dce6812b1539ee96af691ca2e4d9065daa85907d33e5d3"}}, {
-                                                                                                                                                                                                                                                                    "type": 2, "unixTime": 1}]}, {
+                                                                                                                                                                                                                                                                    "type": 2, "slotIndex": 1}]}, {
                                                                                                                                                                                                                                                                         "type": 3, "amount": "5578452198", "nativeTokens": [
                                                                                                                                                                                                                                                                             {
                                                                                                                                                                                                                                                                                 "id": "0x080021bcfa2252a500348f73c939722d65c0354eab33b753ab09bc80a7f592c9a40100000000", "amount": "0x41"}, {
diff --git a/bindings/python/tests/test_output.py b/bindings/python/tests/test_output.py
index 2ec6918444..1d1ff0d4ad 100644
--- a/bindings/python/tests/test_output.py
+++ b/bindings/python/tests/test_output.py
@@ -74,7 +74,7 @@ def test_output():
                     "type": 0,
                     "pubKeyHash": "0x8f463f0c57b86cf52cc69542fb43a2ec87f83b9c47493cce04c1a4616716bed0"
                 },
-                "unixTime": 1659119101
+                "slotIndex": 1659119101
             }
         ]
     }
@@ -101,7 +101,7 @@ def test_output():
             },
             {
                 "type": 2,
-                "unixTime": 1661850262
+                "slotIndex": 1661850262
             }
         ]
     }