diff --git a/graphql-java-support/src/main/java/com/apollographql/federation/graphqljava/Federation.java b/graphql-java-support/src/main/java/com/apollographql/federation/graphqljava/Federation.java
index fba777b1..dad58bfa 100644
--- a/graphql-java-support/src/main/java/com/apollographql/federation/graphqljava/Federation.java
+++ b/graphql-java-support/src/main/java/com/apollographql/federation/graphqljava/Federation.java
@@ -163,15 +163,18 @@ private static RuntimeWiring ensureFederationV2DirectiveDefinitionsExist(
           if (def instanceof DirectiveDefinition
               && !typeRegistry.getDirectiveDefinition(def.getName()).isPresent()) {
             typeRegistry.add(def);
-          } else if (def instanceof ScalarTypeDefinition
-              && !typeRegistry.scalars().containsKey(def.getName())) {
-            typeRegistry.add(def);
-            scalarTypesToAdd.add(
-                GraphQLScalarType.newScalar()
-                    .name(def.getName())
-                    .description(null)
-                    .coercing(_Any.type.getCoercing())
-                    .build());
+          } else if (def instanceof ScalarTypeDefinition) {
+            if (!typeRegistry.scalars().containsKey(def.getName())) {
+              typeRegistry.add(def);
+            }
+            if (!runtimeWiring.getScalars().containsKey(def.getName())) {
+              scalarTypesToAdd.add(
+                  GraphQLScalarType.newScalar()
+                      .name(def.getName())
+                      .description(null)
+                      .coercing(_Any.type.getCoercing())
+                      .build());
+            }
           } else if (def instanceof EnumTypeDefinition
               && !typeRegistry.types().containsKey(def.getName())) {
             typeRegistry.add(def);
diff --git a/graphql-java-support/src/test/java/com/apollographql/federation/graphqljava/FederationTest.java b/graphql-java-support/src/test/java/com/apollographql/federation/graphqljava/FederationTest.java
index 2c35bcfb..19d4f79c 100644
--- a/graphql-java-support/src/test/java/com/apollographql/federation/graphqljava/FederationTest.java
+++ b/graphql-java-support/src/test/java/com/apollographql/federation/graphqljava/FederationTest.java
@@ -356,6 +356,11 @@ public void verifyFederationV2Transformation_progressiveOverride() {
         () -> Federation.transform(schemaSDL).fetchEntities(env -> null).build());
   }
 
+  @Test
+  public void verifyFederationV2Transformation_scalarsDefinedInSchemaButNotWired() {
+    verifyFederationTransformation("schemas/federationV2_defined_scalars.graphql", true);
+  }
+
   private GraphQLSchema verifyFederationTransformation(
       String schemaFileName, boolean isFederationV2) {
     final RuntimeWiring runtimeWiring = RuntimeWiring.newRuntimeWiring().build();
diff --git a/graphql-java-support/src/test/resources/schemas/federationV2_defined_scalars.graphql b/graphql-java-support/src/test/resources/schemas/federationV2_defined_scalars.graphql
new file mode 100644
index 00000000..b451f004
--- /dev/null
+++ b/graphql-java-support/src/test/resources/schemas/federationV2_defined_scalars.graphql
@@ -0,0 +1,84 @@
+extend schema
+  @link(
+    url: "https://specs.apollo.dev/federation/v2.3"
+    import: [
+      "@composeDirective"
+      "@extends"
+      "@external"
+      "@key"
+      "@inaccessible"
+      "@interfaceObject"
+      "@override"
+      "@provides"
+      "@requires"
+      "@shareable"
+      "@tag"
+    ]
+  )
+  @link(url: "https://myspecs.dev/myCustomDirective/v1.0", import: ["@custom"])
+  @composeDirective(name: "@custom")
+
+scalar federation__FieldSet
+
+directive @custom on OBJECT
+directive @key(fields: federation__FieldSet!, resolvable: Boolean = true) repeatable on OBJECT | INTERFACE
+
+type Product
+  @custom
+  @key(fields: "id")
+  @key(fields: "sku package")
+  @key(fields: "sku variation { id }") {
+    id: ID!
+    sku: String
+    package: String
+    variation: ProductVariation
+    dimensions: ProductDimension
+    createdBy: User @provides(fields: "totalProductsCreated")
+    notes: String @tag(name: "internal")
+    research: [ProductResearch!]!
+}
+
+type DeprecatedProduct @key(fields: "sku package") {
+  sku: String!
+  package: String!
+  reason: String
+  createdBy: User
+}
+
+type ProductVariation {
+  id: ID!
+}
+
+type ProductResearch @key(fields: "study { caseNumber }") {
+  study: CaseStudy!
+  outcome: String
+}
+
+type CaseStudy {
+  caseNumber: ID!
+  description: String
+}
+
+type ProductDimension @shareable {
+  size: String
+  weight: Float
+  unit: String @inaccessible
+}
+
+type Query {
+  product(id: ID!): Product
+  deprecatedProduct(sku: String!, package: String!): DeprecatedProduct @deprecated(reason: "Use product query instead")
+}
+
+type User @key(fields: "email") {
+  averageProductsCreatedPerYear: Int @requires(fields: "totalProductsCreated yearsOfEmployment")
+  email: ID! @external
+  name: String @override(from: "users")
+  totalProductsCreated: Int @external
+  yearsOfEmployment: Int! @external
+}
+
+type Inventory @interfaceObject @key(fields: "id") {
+  id: ID!
+  deprecatedProducts: [DeprecatedProduct!]!
+}
diff --git a/graphql-java-support/src/test/resources/schemas/federationV2_defined_scalars_federated.graphql b/graphql-java-support/src/test/resources/schemas/federationV2_defined_scalars_federated.graphql
new file mode 100644
index 00000000..2ffa9871
--- /dev/null
+++ b/graphql-java-support/src/test/resources/schemas/federationV2_defined_scalars_federated.graphql
@@ -0,0 +1,104 @@
+schema @composeDirective(name : "@custom") @link(import : ["@composeDirective", "@extends", "@external", "@key", "@inaccessible", "@interfaceObject", "@override", "@provides", "@requires", "@shareable", "@tag"], url : "https://specs.apollo.dev/federation/v2.3") @link(import : ["@custom"], url : "https://myspecs.dev/myCustomDirective/v1.0"){
+  query: Query
+}
+
+directive @composeDirective(name: String!) repeatable on SCHEMA
+
+directive @custom on OBJECT
+
+directive @extends on OBJECT | INTERFACE
+
+directive @external on OBJECT | FIELD_DEFINITION
+
+directive @inaccessible on SCALAR | OBJECT | FIELD_DEFINITION | ARGUMENT_DEFINITION | INTERFACE | UNION | ENUM | ENUM_VALUE | INPUT_OBJECT | INPUT_FIELD_DEFINITION
+
+directive @interfaceObject on OBJECT
+
+directive @key(fields: federation__FieldSet!, resolvable: Boolean = true) repeatable on OBJECT | INTERFACE
+
+directive @link(as: String, for: link__Purpose, import: [link__Import], url: String!) repeatable on SCHEMA
+
+directive @override(from: String!) on FIELD_DEFINITION
+
+directive @provides(fields: federation__FieldSet!) on FIELD_DEFINITION
+
+directive @requires(fields: federation__FieldSet!) on FIELD_DEFINITION
+
+directive @shareable repeatable on OBJECT | FIELD_DEFINITION
+
+directive @tag(name: String!) repeatable on SCALAR | OBJECT | FIELD_DEFINITION | ARGUMENT_DEFINITION | INTERFACE | UNION | ENUM | ENUM_VALUE | INPUT_OBJECT | INPUT_FIELD_DEFINITION
+
+union _Entity = DeprecatedProduct | Inventory | Product | ProductResearch | User
+
+type CaseStudy {
+  caseNumber: ID!
+  description: String
+}
+
+type DeprecatedProduct @key(fields : "sku package", resolvable : true) {
+  createdBy: User
+  package: String!
+  reason: String
+  sku: String!
+}
+
+type Inventory @interfaceObject @key(fields : "id", resolvable : true) {
+  deprecatedProducts: [DeprecatedProduct!]!
+  id: ID!
+}
+
+type Product @custom @key(fields : "id", resolvable : true) @key(fields : "sku package", resolvable : true) @key(fields : "sku variation { id }", resolvable : true) {
+  createdBy: User @provides(fields : "totalProductsCreated")
+  dimensions: ProductDimension
+  id: ID!
+  notes: String @tag(name : "internal")
+  package: String
+  research: [ProductResearch!]!
+  sku: String
+  variation: ProductVariation
+}
+
+type ProductDimension @shareable {
+  size: String
+  unit: String @inaccessible
+  weight: Float
+}
+
+type ProductResearch @key(fields : "study { caseNumber }", resolvable : true) {
+  outcome: String
+  study: CaseStudy!
+}
+
+type ProductVariation {
+  id: ID!
+}
+
+type Query {
+  _entities(representations: [_Any!]!): [_Entity]!
+  _service: _Service!
+  deprecatedProduct(package: String!, sku: String!): DeprecatedProduct @deprecated(reason : "Use product query instead")
+  product(id: ID!): Product
+}
+
+type User @key(fields : "email", resolvable : true) {
+  averageProductsCreatedPerYear: Int @requires(fields : "totalProductsCreated yearsOfEmployment")
+  email: ID! @external
+  name: String @override(from : "users")
+  totalProductsCreated: Int @external
+  yearsOfEmployment: Int! @external
+}
+
+type _Service {
+  sdl: String!
+}
+
+enum link__Purpose {
+  EXECUTION
+  SECURITY
+}
+
+scalar _Any
+
+scalar federation__FieldSet
+
+scalar link__Import