diff --git a/app/serializers/commentaire_serializer.rb b/app/serializers/commentaire_serializer.rb
index 19360bfdf..3cc79c8a2 100644
--- a/app/serializers/commentaire_serializer.rb
+++ b/app/serializers/commentaire_serializer.rb
@@ -4,6 +4,10 @@ class CommentaireSerializer < ActiveModel::Serializer
     :created_at,
     :attachment
 
+  def created_at
+    object.created_at&.in_time_zone('UTC')
+  end
+
   def attachment
     object.file_url
   end
diff --git a/app/serializers/dossier_serializer.rb b/app/serializers/dossier_serializer.rb
index a35e5ba57..0acd0ed29 100644
--- a/app/serializers/dossier_serializer.rb
+++ b/app/serializers/dossier_serializer.rb
@@ -50,17 +50,29 @@ class DossierSerializer < ActiveModel::Serializer
   end
 
   def initiated_at
-    object.en_construction_at
+    object.en_construction_at&.in_time_zone('UTC')
   end
 
   def received_at
-    object.en_instruction_at
+    object.en_instruction_at&.in_time_zone('UTC')
   end
 
   def instructeurs
     object.followers_gestionnaires.pluck(:email)
   end
 
+  def created_at
+    object.created_at&.in_time_zone('UTC')
+  end
+
+  def updated_at
+    object.updated_at&.in_time_zone('UTC')
+  end
+
+  def processed_at
+    object.processed_at&.in_time_zone('UTC')
+  end
+
   private
 
   def user_geometry(dossier)
diff --git a/app/serializers/dossiers_serializer.rb b/app/serializers/dossiers_serializer.rb
index a1c225229..6751e5c53 100644
--- a/app/serializers/dossiers_serializer.rb
+++ b/app/serializers/dossiers_serializer.rb
@@ -4,8 +4,12 @@ class DossiersSerializer < ActiveModel::Serializer
     :initiated_at,
     :state
 
+  def updated_at
+    object.updated_at&.in_time_zone('UTC')
+  end
+
   def initiated_at
-    object.en_construction_at
+    object.en_construction_at&.in_time_zone('UTC')
   end
 
   def state
diff --git a/app/serializers/piece_justificative_serializer.rb b/app/serializers/piece_justificative_serializer.rb
index fdcf1d2c9..0a7a7a724 100644
--- a/app/serializers/piece_justificative_serializer.rb
+++ b/app/serializers/piece_justificative_serializer.rb
@@ -4,4 +4,8 @@ class PieceJustificativeSerializer < ActiveModel::Serializer
     :content_url
 
   has_one :user
+
+  def created_at
+    object.created_at&.in_time_zone('UTC')
+  end
 end
diff --git a/app/serializers/procedure_serializer.rb b/app/serializers/procedure_serializer.rb
index bd5605a6c..d1a7a491c 100644
--- a/app/serializers/procedure_serializer.rb
+++ b/app/serializers/procedure_serializer.rb
@@ -18,6 +18,10 @@ class ProcedureSerializer < ActiveModel::Serializer
   has_many :types_de_champ_private, serializer: TypeDeChampSerializer
   has_many :types_de_piece_justificative, serializer: TypeDePieceJustificativeSerializer
 
+  def archived_at
+    object.archived_at&.in_time_zone('UTC')
+  end
+
   def link
     if object.path.present?
       if object.brouillon_avec_lien?
diff --git a/spec/controllers/api/v1/dossiers_controller_spec.rb b/spec/controllers/api/v1/dossiers_controller_spec.rb
index 6873f031c..47ced3e71 100644
--- a/spec/controllers/api/v1/dossiers_controller_spec.rb
+++ b/spec/controllers/api/v1/dossiers_controller_spec.rb
@@ -75,8 +75,8 @@ describe API::V1::DossiersController do
         describe 'dossier' do
           subject { super().first }
           it { expect(subject[:id]).to eq(dossier.id) }
-          it { expect(subject[:updated_at]).to eq("2008-09-01T10:05:00.000+02:00") }
-          it { expect(subject[:initiated_at]).to eq("2008-09-01T10:06:00.000+02:00") }
+          it { expect(subject[:updated_at]).to eq("2008-09-01T08:05:00.000Z") }
+          it { expect(subject[:initiated_at]).to eq("2008-09-01T08:06:00.000Z") }
           it { expect(subject[:state]).to eq("initiated") }
           it { expect(subject.keys.size).to eq(4) }
         end
@@ -148,8 +148,8 @@ describe API::V1::DossiersController do
 
         it { expect(subject[:id]).to eq(dossier.id) }
         it { expect(subject[:state]).to eq(dossier.state) }
-        it { expect(subject[:created_at]).to eq('2008-09-01T10:05:00.000+02:00') }
-        it { expect(subject[:updated_at]).to eq('2008-09-01T10:05:00.000+02:00') }
+        it { expect(subject[:created_at]).to eq('2008-09-01T08:05:00.000Z') }
+        it { expect(subject[:updated_at]).to eq('2008-09-01T08:05:00.000Z') }
         it { expect(subject[:archived]).to eq(dossier.archived) }
 
         it { expect(subject.keys).to match_array(field_list) }
@@ -337,7 +337,7 @@ describe API::V1::DossiersController do
           it { expect(subject.size).to eq 2 }
 
           it { expect(subject.first[:body]).to eq 'plop' }
-          it { expect(subject.first[:created_at]).to eq '2016-03-14T14:00:00.000+01:00' }
+          it { expect(subject.first[:created_at]).to eq '2016-03-14T13:00:00.000Z' }
           it { expect(subject.first[:email]).to eq 'plop@plip.com' }
         end