diff --git a/apps/cs/src/cs_bank_card_database.erl b/apps/cs/src/cs_bank_card_database.erl
index 3a75df4..8ee0f2f 100644
--- a/apps/cs/src/cs_bank_card_database.erl
+++ b/apps/cs/src/cs_bank_card_database.erl
@@ -205,6 +205,8 @@ find_or_create(BankCardToken, PartyRef, CardMask) ->
         ON target.bank_card_token = source.bank_card_token AND target.deleted_at IS NULL
         WHEN NOT MATCHED THEN
             INSERT (bank_card_token, card_mask) VALUES (source.bank_card_token, source.card_mask)
+        WHEN MATCHED THEN
+            UPDATE SET card_mask = source.card_mask
         RETURNING id
     )
     MERGE INTO bank_card_party AS target
@@ -212,6 +214,8 @@ find_or_create(BankCardToken, PartyRef, CardMask) ->
     ON target.bank_card_id = source.bank_card_id AND target.party_ref = source.party_ref
     WHEN MATCHED AND target.deleted_at IS NOT NULL THEN
         UPDATE SET deleted_at = NULL, created_at = NOW()
+    WHEN MATCHED AND target.deleted_at IS NULL THEN
+        UPDATE SET created_at = target.created_at
     WHEN NOT MATCHED THEN
         INSERT (bank_card_id, party_ref) VALUES (source.bank_card_id, source.party_ref)
     RETURNING (SELECT id FROM card)
diff --git a/apps/cs/test/cs_integration_SUITE.erl b/apps/cs/test/cs_integration_SUITE.erl
index f6ef4f3..496673a 100644
--- a/apps/cs/test/cs_integration_SUITE.erl
+++ b/apps/cs/test/cs_integration_SUITE.erl
@@ -20,6 +20,8 @@
     delete_customer_test/1,
     customer_not_found_test/1,
     add_bank_card_test/1,
+    add_bank_card_idempotent_test/1,
+    add_bank_card_idempotent_different_customers_test/1,
     remove_bank_card_test/1,
     add_payment_test/1,
     get_payments_test/1,
@@ -45,6 +47,8 @@ groups() ->
             create_customer_test,
             get_customer_test,
             add_bank_card_test,
+            add_bank_card_idempotent_test,
+            add_bank_card_idempotent_different_customers_test,
             add_payment_test,
             get_payments_test,
             get_payments_pagination_test,
@@ -158,6 +162,34 @@ add_bank_card_test(Config) ->
     ?assertEqual(<<"token-1">>, BankCard#customer_BankCard.bank_card_token),
     ok.
 
+%% Adding the same bank card token to the same customer twice should succeed (idempotent)
+add_bank_card_idempotent_test(Config) ->
+    Client = ?config(client, Config),
+    {ok, Customer} = cs_client:create_customer(
+        #customer_CustomerParams{
+            party_ref = #domain_PartyConfigRef{id = <<"party-idempotent">>}
+        },
+        Client
+    ),
+    CustomerId = Customer#customer_Customer.id,
+    Params = #customer_BankCardParams{bank_card_token = <<"token-idempotent">>},
+    {ok, BankCard1} = cs_client:add_bank_card(CustomerId, Params, Client),
+    {ok, BankCard2} = cs_client:add_bank_card(CustomerId, Params, Client),
+    ?assertEqual(BankCard1#customer_BankCard.id, BankCard2#customer_BankCard.id),
+    ok.
+
+%% Same bank card token added to two different customers of the same party should reuse the card
+add_bank_card_idempotent_different_customers_test(Config) ->
+    Client = ?config(client, Config),
+    PartyRef = #domain_PartyConfigRef{id = <<"party-shared-card">>},
+    {ok, Customer1} = cs_client:create_customer(#customer_CustomerParams{party_ref = PartyRef}, Client),
+    {ok, Customer2} = cs_client:create_customer(#customer_CustomerParams{party_ref = PartyRef}, Client),
+    Params = #customer_BankCardParams{bank_card_token = <<"token-shared">>},
+    {ok, BankCard1} = cs_client:add_bank_card(Customer1#customer_Customer.id, Params, Client),
+    {ok, BankCard2} = cs_client:add_bank_card(Customer2#customer_Customer.id, Params, Client),
+    ?assertEqual(BankCard1#customer_BankCard.id, BankCard2#customer_BankCard.id),
+    ok.
+
 remove_bank_card_test(Config) ->
     Client = ?config(client, Config),
     {ok, Customer} = cs_client:create_customer(