diff --git a/docs/ApiValidationRules.md b/docs/ApiValidationRules.md
index c080ae0..8a38a91 100644
--- a/docs/ApiValidationRules.md
+++ b/docs/ApiValidationRules.md
@@ -147,6 +147,7 @@ The id field is required, missing fields will not be updated.
     | Field | Validation |
     |-------|------------|
     | eta_berth, etd_berth, lock_time, zone_entry, operations_start, operations_end | if set these values must be in the future|
+    | eta_interval_end, etd_interval_end | if set these values must be in the future. They must be larger than their ETA/ETD counterparts. |
     | remarks, berth_info | must be <= 512 chars |
     | participant_type | must not be BSMD |
 
diff --git a/src/server/BreCal/schemas/model.py b/src/server/BreCal/schemas/model.py
index a21fb20..14bceda 100644
--- a/src/server/BreCal/schemas/model.py
+++ b/src/server/BreCal/schemas/model.py
@@ -436,6 +436,21 @@ class TimesSchema(Schema):
         # when 'value' is 'None', a ValidationError is not issued.
         valid_time = validate_time_is_in_not_too_distant_future(raise_validation_error=True, value=value, months=12)
         return
+    
+    @validates("eta_interval_end")
+    def validate_eta_interval_end(self, value):
+        # violation when time is not in the future, but also does not exceed a threshold for the 'reasonable' future
+        # when 'value' is 'None', a ValidationError is not issued.
+        valid_time = validate_time_is_in_not_too_distant_future(raise_validation_error=True, value=value, months=12)
+        return
+
+    @validates("etd_interval_end")
+    def validate_etd_interval_end(self, value):
+        # violation when time is not in the future, but also does not exceed a threshold for the 'reasonable' future
+        # when 'value' is 'None', a ValidationError is not issued.
+        valid_time = validate_time_is_in_not_too_distant_future(raise_validation_error=True, value=value, months=12)
+        return
+
 
 # deserialize PUT object target
 
diff --git a/src/server/BreCal/validators/input_validation_times.py b/src/server/BreCal/validators/input_validation_times.py
index 0385220..37b70b8 100644
--- a/src/server/BreCal/validators/input_validation_times.py
+++ b/src/server/BreCal/validators/input_validation_times.py
@@ -167,6 +167,17 @@ class InputValidationTimes():
 
         if ParticipantType.BSMD in loadedModel["participant_type"]:
             raise ValidationError(f"current user belongs to BSMD. Cannot post times datasets. Found user data: {user_data}")
+        
+        if (loadedModel["etd_interval_end"] is not None) and (loadedModel["etd_berth"] is not None):
+            time_end_after_time_start = loadedModel["etd_interval_end"] >= loadedModel["etd_berth"]
+            if not time_end_after_time_start:
+                raise ValidationError(f"The provided time interval for the estimated departure time is invalid. The interval end takes place before the interval start. Found interval data: {loadedModel['etd_berth']} to {loadedModel['etd_interval_end']}")
+
+
+        if (loadedModel["eta_interval_end"] is not None) and (loadedModel["eta_berth"] is not None):
+            time_end_after_time_start = loadedModel["eta_interval_end"] >= loadedModel["eta_berth"]
+            if not time_end_after_time_start:
+                raise ValidationError(f"The provided time interval for the estimated arrival time is invalid. The interval begin takes place after the interval end. Found interval data: {loadedModel['eta_berth']} to {loadedModel['eta_interval_end']}")
         return
     
     @staticmethod