diff --git a/pyproject.toml b/pyproject.toml
index c455fcc..174415e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,7 +19,7 @@ keywords=["stac", "pydantic", "validation"]
 authors=[{ name = "Arturo Engineering", email = "engineering@arturo.ai"}]
 license= { text = "MIT" }
 requires-python=">=3.8"
-dependencies = ["click>=8.1.7", "pydantic>=2.4.1", "geojson-pydantic>=1.0.0"]
+dependencies = ["click>=8.1.7", "pydantic>=2.4.1", "geojson-pydantic>=1.0.0", "ciso8601~=2.3"]
 dynamic = ["version", "readme"]
 
 [project.scripts]
diff --git a/stac_pydantic/api/search.py b/stac_pydantic/api/search.py
index bc32099..a005369 100644
--- a/stac_pydantic/api/search.py
+++ b/stac_pydantic/api/search.py
@@ -1,6 +1,7 @@
 from datetime import datetime as dt
 from typing import Any, Dict, List, Optional, Tuple, Union, cast
 
+from ciso8601 import parse_rfc3339
 from geojson_pydantic.geometries import (  # type: ignore
     GeometryCollection,
     LineString,
@@ -16,7 +17,6 @@
 from stac_pydantic.api.extensions.query import Operator
 from stac_pydantic.api.extensions.sort import SortExtension
 from stac_pydantic.shared import BBox
-from stac_pydantic.utils import parse_datetime
 
 Intersection = Union[
     Point,
@@ -50,16 +50,16 @@ def start_date(self) -> Optional[dt]:
             return None
         if values[0] == ".." or values[0] == "":
             return None
-        return parse_datetime(values[0])
+        return parse_rfc3339(values[0])
 
     @property
     def end_date(self) -> Optional[dt]:
         values = (self.datetime or "").split("/")
         if len(values) == 1:
-            return parse_datetime(values[0])
+            return parse_rfc3339(values[0])
         if values[1] == ".." or values[1] == "":
             return None
-        return parse_datetime(values[1])
+        return parse_rfc3339(values[1])
 
     # Check https://docs.pydantic.dev/dev-v2/migration/#changes-to-validators for more information.
     @model_validator(mode="before")
@@ -109,17 +109,18 @@ def validate_datetime(cls, v: str) -> str:
             # Single date is interpreted as end date
             values = ["..", v]
 
-        dates = []
+        dates: List[dt] = []
         for value in values:
             if value == ".." or value == "":
-                dates.append("..")
                 continue
 
-            parse_datetime(value)
-            dates.append(value)
+            dates.append(parse_rfc3339(value))
 
-        if ".." not in dates:
-            if parse_datetime(dates[0]) > parse_datetime(dates[1]):
+        if len(values) > 2:
+            raise ValueError("Invalid datetime range, must match format (begin_date, end_date)")
+
+        if not {"..", ""}.intersection(set(values)):
+            if dates[0] > dates[1]:
                 raise ValueError(
                     "Invalid datetime range, must match format (begin_date, end_date)"
                 )
diff --git a/stac_pydantic/item.py b/stac_pydantic/item.py
index 8d958b9..452b51a 100644
--- a/stac_pydantic/item.py
+++ b/stac_pydantic/item.py
@@ -1,6 +1,7 @@
 from datetime import datetime as dt
 from typing import Any, Dict, List, Optional, Union
 
+from ciso8601 import parse_rfc3339
 from geojson_pydantic import Feature
 from pydantic import (
     AnyUrl,
@@ -19,7 +20,6 @@
     StacBaseModel,
     StacCommonMetadata,
 )
-from stac_pydantic.utils import parse_datetime
 from stac_pydantic.version import STAC_VERSION
 
 
@@ -47,13 +47,13 @@ def validate_datetime(cls, data: Dict[str, Any]) -> Dict[str, Any]:
                 )
 
         if isinstance(datetime, str):
-            data["datetime"] = parse_datetime(datetime)
+            data["datetime"] = parse_rfc3339(datetime)
 
         if isinstance(start_datetime, str):
-            data["start_datetime"] = parse_datetime(start_datetime)
+            data["start_datetime"] = parse_rfc3339(start_datetime)
 
         if isinstance(end_datetime, str):
-            data["end_datetime"] = parse_datetime(end_datetime)
+            data["end_datetime"] = parse_rfc3339(end_datetime)
 
         return data
 
diff --git a/stac_pydantic/utils.py b/stac_pydantic/utils.py
index ef8cf51..1bdca60 100644
--- a/stac_pydantic/utils.py
+++ b/stac_pydantic/utils.py
@@ -1,9 +1,5 @@
-import json
-from datetime import datetime
 from enum import Enum
-from typing import Any, Callable, List
-
-from pydantic import TypeAdapter
+from typing import Any, List
 
 
 class AutoValueEnum(Enum):
@@ -11,8 +7,3 @@ def _generate_next_value_(  # type: ignore
         name: str, start: int, count: int, last_values: List[Any]
     ) -> Any:
         return name
-
-
-parse_datetime: Callable[[Any], datetime] = lambda x: TypeAdapter(
-    datetime
-).validate_json(json.dumps(x))
diff --git a/tests/api/test_search.py b/tests/api/test_search.py
index fc04a9c..ab44566 100644
--- a/tests/api/test_search.py
+++ b/tests/api/test_search.py
@@ -1,5 +1,5 @@
 import time
-from datetime import datetime, timezone
+from datetime import datetime, timezone, timedelta
 
 import pytest
 from pydantic import ValidationError
@@ -93,6 +93,12 @@ def test_invalid_temporal_search():
     with pytest.raises(ValidationError):
         Search(collections=["collection1"], datetime=utcnow)
 
+    t1 = datetime.utcnow()
+    t2 = t1 + timedelta(seconds=100)
+    t3 = t2 + timedelta(seconds=100)
+    with pytest.raises(ValidationError):
+        Search(collections=["collection1"], datetime=f"{t1.strftime(DATETIME_RFC339)}/{t2.strftime(DATETIME_RFC339)}/{t3.strftime(DATETIME_RFC339)}",)
+
     # End date is before start date
     start = datetime.utcnow()
     time.sleep(2)