diff --git a/backend/src/main/kotlin/fr/gouv/cnsp/monitorfish/domain/entities/vessel/Vessel.kt b/backend/src/main/kotlin/fr/gouv/cnsp/monitorfish/domain/entities/vessel/Vessel.kt
index bcfbed59b7..5eb9c33ee8 100644
--- a/backend/src/main/kotlin/fr/gouv/cnsp/monitorfish/domain/entities/vessel/Vessel.kt
+++ b/backend/src/main/kotlin/fr/gouv/cnsp/monitorfish/domain/entities/vessel/Vessel.kt
@@ -37,8 +37,58 @@ data class Vessel(
     val underCharter: Boolean? = null,
 ) {
     fun getNationalIdentifier(): String {
-        val identifier = internalReferenceNumber?.replace("FRA000", "") ?: ""
+        val internalReferenceNumberCountryCode = LIKELY_CONTROLLED_COUNTRY_CODES.find { countryAlpha3 -> internalReferenceNumber?.contains(countryAlpha3) ?: false }
+        val identifier = internalReferenceNumber?.replace("${internalReferenceNumberCountryCode}000", "") ?: ""
+
+        if (districtCode.isNullOrEmpty()) {
+            return identifier
+        }
 
         return "$districtCode$identifier"
     }
 }
+
+val LIKELY_CONTROLLED_COUNTRY_CODES = listOf(
+    CountryCode.FR.alpha3,
+    CountryCode.RU.alpha3,
+    CountryCode.KR.alpha3,
+    CountryCode.JP.alpha3,
+    CountryCode.LY.alpha3,
+    CountryCode.VE.alpha3,
+    CountryCode.SC.alpha3,
+    CountryCode.AU.alpha3,
+    CountryCode.CN.alpha3,
+    CountryCode.MG.alpha3,
+    CountryCode.BR.alpha3,
+    CountryCode.PL.alpha3,
+    CountryCode.VU.alpha3,
+    CountryCode.KM.alpha3,
+    CountryCode.MC.alpha3,
+    CountryCode.BW.alpha3,
+    CountryCode.AI.alpha3,
+    CountryCode.LK.alpha3,
+    CountryCode.TW.alpha3,
+    CountryCode.TT.alpha3,
+    CountryCode.FO.alpha3,
+    CountryCode.GY.alpha3,
+    CountryCode.PA.alpha3,
+    CountryCode.SX.alpha3,
+    CountryCode.TN.alpha3,
+    CountryCode.TR.alpha3,
+    CountryCode.AL.alpha3,
+    CountryCode.GD.alpha3,
+    CountryCode.DZ.alpha3,
+    CountryCode.SX.alpha3,
+    CountryCode.BE.alpha3,
+    CountryCode.DK.alpha3,
+    CountryCode.DE.alpha3,
+    CountryCode.EE.alpha3,
+    CountryCode.IE.alpha3,
+    CountryCode.ES.alpha3,
+    CountryCode.IT.alpha3,
+    CountryCode.NL.alpha3,
+    CountryCode.NO.alpha3,
+    CountryCode.PT.alpha3,
+    CountryCode.SE.alpha3,
+    CountryCode.GB.alpha3,
+)
diff --git a/backend/src/test/kotlin/fr/gouv/cnsp/monitorfish/domain/entities/vessel/VesselUTests.kt b/backend/src/test/kotlin/fr/gouv/cnsp/monitorfish/domain/entities/vessel/VesselUTests.kt
new file mode 100644
index 0000000000..4542dd2163
--- /dev/null
+++ b/backend/src/test/kotlin/fr/gouv/cnsp/monitorfish/domain/entities/vessel/VesselUTests.kt
@@ -0,0 +1,71 @@
+package fr.gouv.cnsp.monitorfish.domain.entities.vessel
+
+import com.neovisionaries.i18n.CountryCode
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.extension.ExtendWith
+import org.springframework.test.context.junit.jupiter.SpringExtension
+
+@ExtendWith(SpringExtension::class)
+class VesselUTests {
+    @Test
+    fun `getNationalIdentifier should return the identifier for a FR vessel`() {
+        // Given
+        val vessel = Vessel(
+            id = 1,
+            internalReferenceNumber = "FRA00022680",
+            vesselName = "MY AWESOME VESSEL",
+            flagState = CountryCode.FR,
+            declaredFishingGears = listOf("Trémails"),
+            vesselType = "Fishing",
+            districtCode = "AY",
+        )
+
+        // When
+        val nationalIdentifier = vessel.getNationalIdentifier()
+
+        // Then
+        assertThat(nationalIdentifier).isEqualTo("AY22680")
+    }
+
+    @Test
+    fun `getNationalIdentifier should return the identifier for a FR vessel When district code is null`() {
+        // Given
+        val vessel = Vessel(
+            id = 1,
+            internalReferenceNumber = "FRA00022680",
+            vesselName = "MY AWESOME VESSEL",
+            flagState = CountryCode.FR,
+            declaredFishingGears = listOf("Trémails"),
+            vesselType = "Fishing",
+            districtCode = "",
+        )
+
+        // When
+        val nationalIdentifier = vessel.getNationalIdentifier()
+
+        // Then
+        assertThat(nationalIdentifier).isEqualTo("22680")
+    }
+
+    @Test
+    fun `getNationalIdentifier should return the identifier for a GB vessel`() {
+        // Given
+        val vessel = Vessel(
+            id = 1,
+            internalReferenceNumber = "GBR00022680",
+            vesselName = "MY AWESOME VESSEL",
+            flagState = CountryCode.GB,
+            declaredFishingGears = listOf("Trémails"),
+            vesselType = "Fishing",
+            districtCode = "AY",
+        )
+
+        // When
+        val nationalIdentifier = vessel.getNationalIdentifier()
+
+        // Then
+        assertThat(nationalIdentifier).isEqualTo("AY22680")
+    }
+}