diff --git a/src/spikeinterface/core/sorting_tools.py b/src/spikeinterface/core/sorting_tools.py
index 2313e7d253..02f4529a98 100644
--- a/src/spikeinterface/core/sorting_tools.py
+++ b/src/spikeinterface/core/sorting_tools.py
@@ -47,7 +47,7 @@ def spike_vector_to_spike_trains(spike_vector: list[np.array], unit_ids: np.arra
     return spike_trains
 
 
-def spike_vector_to_indices(spike_vector: list[np.array], unit_ids: np.array):
+def spike_vector_to_indices(spike_vector: list[np.array], unit_ids: np.array, absolute_index: bool = False):
     """
     Similar to spike_vector_to_spike_trains but instead having the spike_trains (aka spike times) return
     spike indices by segment and units.
@@ -61,6 +61,11 @@ def spike_vector_to_indices(spike_vector: list[np.array], unit_ids: np.array):
         List of spike vectors optained with sorting.to_spike_vector(concatenated=False)
     unit_ids: np.array
         Unit ids
+    absolute_index: bool, default False
+        It True, return absolute spike indices. If False, spike indices are relative to the segment.
+        When a unique spike vector is used,  then absolute_index should be True.
+        When a list of spikes per segment is used, then absolute_index should be False.
+
     Returns
     -------
     spike_indices: dict[dict]:
@@ -82,10 +87,16 @@ def spike_vector_to_indices(spike_vector: list[np.array], unit_ids: np.array):
 
     num_units = unit_ids.size
     spike_indices = {}
+
+    total_spikes = 0
     for segment_index, spikes in enumerate(spike_vector):
         indices = np.arange(spikes.size, dtype=np.int64)
+        if absolute_index:
+            indices += total_spikes
+            total_spikes += spikes.size
         unit_indices = np.array(spikes["unit_index"]).astype(np.int64, copy=False)
         list_of_spike_indices = vector_to_list_of_spiketrain(indices, unit_indices, num_units)
+
         spike_indices[segment_index] = dict(zip(unit_ids, list_of_spike_indices))
 
     return spike_indices
diff --git a/src/spikeinterface/postprocessing/spike_amplitudes.py b/src/spikeinterface/postprocessing/spike_amplitudes.py
index 09b46362e5..aebfd1fd78 100644
--- a/src/spikeinterface/postprocessing/spike_amplitudes.py
+++ b/src/spikeinterface/postprocessing/spike_amplitudes.py
@@ -127,7 +127,7 @@ def _get_data(self, outputs="numpy"):
         elif outputs == "by_unit":
             unit_ids = self.sorting_analyzer.unit_ids
             spike_vector = self.sorting_analyzer.sorting.to_spike_vector(concatenated=False)
-            spike_indices = spike_vector_to_indices(spike_vector, unit_ids)
+            spike_indices = spike_vector_to_indices(spike_vector, unit_ids, absolute_index=True)
             amplitudes_by_units = {}
             for segment_index in range(self.sorting_analyzer.sorting.get_num_segments()):
                 amplitudes_by_units[segment_index] = {}
diff --git a/src/spikeinterface/postprocessing/spike_locations.py b/src/spikeinterface/postprocessing/spike_locations.py
index 96e01a68c4..52a91342b6 100644
--- a/src/spikeinterface/postprocessing/spike_locations.py
+++ b/src/spikeinterface/postprocessing/spike_locations.py
@@ -138,7 +138,7 @@ def _get_data(self, outputs="numpy"):
         elif outputs == "by_unit":
             unit_ids = self.sorting_analyzer.unit_ids
             spike_vector = self.sorting_analyzer.sorting.to_spike_vector(concatenated=False)
-            spike_indices = spike_vector_to_indices(spike_vector, unit_ids)
+            spike_indices = spike_vector_to_indices(spike_vector, unit_ids, absolute_index=True)
             spike_locations_by_units = {}
             for segment_index in range(self.sorting_analyzer.sorting.get_num_segments()):
                 spike_locations_by_units[segment_index] = {}