diff --git a/pkg/apis/discovery/v1/zz_generated.validations.go b/pkg/apis/discovery/v1/zz_generated.validations.go
index 6a7d813549c..2766f592446 100644
--- a/pkg/apis/discovery/v1/zz_generated.validations.go
+++ b/pkg/apis/discovery/v1/zz_generated.validations.go
@@ -91,7 +91,25 @@ func Validate_Endpoint(ctx context.Context, op operation.Operation, fldPath *fie
 func Validate_EndpointSlice(ctx context.Context, op operation.Operation, fldPath *field.Path, obj, oldObj *discoveryv1.EndpointSlice) (errs field.ErrorList) {
 	// field discoveryv1.EndpointSlice.TypeMeta has no validation
 	// field discoveryv1.EndpointSlice.ObjectMeta has no validation
-	// field discoveryv1.EndpointSlice.AddressType has no validation
+
+	// field discoveryv1.EndpointSlice.AddressType
+	errs = append(errs,
+		func(fldPath *field.Path, obj, oldObj *discoveryv1.AddressType, oldValueCorrelated bool) (errs field.ErrorList) {
+			// don't revalidate unchanged data
+			if oldValueCorrelated && op.Type == operation.Update && (obj == oldObj || (obj != nil && oldObj != nil && *obj == *oldObj)) {
+				return nil
+			}
+			// call field-attached validations
+			earlyReturn := false
+			if e := validate.RequiredValue(ctx, op, fldPath, obj, oldObj); len(e) != 0 {
+				errs = append(errs, e...)
+				earlyReturn = true
+			}
+			if earlyReturn {
+				return // do not proceed
+			}
+			return
+		}(fldPath.Child("addressType"), &obj.AddressType, safe.Field(oldObj, func(oldObj *discoveryv1.EndpointSlice) *discoveryv1.AddressType { return &oldObj.AddressType }), oldObj != nil)...)
 
 	// field discoveryv1.EndpointSlice.Endpoints
 	errs = append(errs,
diff --git a/pkg/apis/discovery/v1beta1/zz_generated.validations.go b/pkg/apis/discovery/v1beta1/zz_generated.validations.go
index ef44355086f..ba337446aa7 100644
--- a/pkg/apis/discovery/v1beta1/zz_generated.validations.go
+++ b/pkg/apis/discovery/v1beta1/zz_generated.validations.go
@@ -90,7 +90,25 @@ func Validate_Endpoint(ctx context.Context, op operation.Operation, fldPath *fie
 func Validate_EndpointSlice(ctx context.Context, op operation.Operation, fldPath *field.Path, obj, oldObj *discoveryv1beta1.EndpointSlice) (errs field.ErrorList) {
 	// field discoveryv1beta1.EndpointSlice.TypeMeta has no validation
 	// field discoveryv1beta1.EndpointSlice.ObjectMeta has no validation
-	// field discoveryv1beta1.EndpointSlice.AddressType has no validation
+
+	// field discoveryv1beta1.EndpointSlice.AddressType
+	errs = append(errs,
+		func(fldPath *field.Path, obj, oldObj *discoveryv1beta1.AddressType, oldValueCorrelated bool) (errs field.ErrorList) {
+			// don't revalidate unchanged data
+			if oldValueCorrelated && op.Type == operation.Update && (obj == oldObj || (obj != nil && oldObj != nil && *obj == *oldObj)) {
+				return nil
+			}
+			// call field-attached validations
+			earlyReturn := false
+			if e := validate.RequiredValue(ctx, op, fldPath, obj, oldObj); len(e) != 0 {
+				errs = append(errs, e...)
+				earlyReturn = true
+			}
+			if earlyReturn {
+				return // do not proceed
+			}
+			return
+		}(fldPath.Child("addressType"), &obj.AddressType, safe.Field(oldObj, func(oldObj *discoveryv1beta1.EndpointSlice) *discoveryv1beta1.AddressType { return &oldObj.AddressType }), oldObj != nil)...)
 
 	// field discoveryv1beta1.EndpointSlice.Endpoints
 	errs = append(errs,
diff --git a/pkg/apis/discovery/validation/validation.go b/pkg/apis/discovery/validation/validation.go
index 9c9e441a583..be93d297206 100644
--- a/pkg/apis/discovery/validation/validation.go
+++ b/pkg/apis/discovery/validation/validation.go
@@ -207,7 +207,7 @@ func validateAddressType(addressType discovery.AddressType) field.ErrorList {
 	allErrs := field.ErrorList{}
 
 	if addressType == "" {
-		allErrs = append(allErrs, field.Required(field.NewPath("addressType"), ""))
+		allErrs = append(allErrs, field.Required(field.NewPath("addressType"), "").MarkCoveredByDeclarative())
 	} else if !supportedAddressTypes.Has(addressType) {
 		allErrs = append(allErrs, field.NotSupported(field.NewPath("addressType"), addressType, sets.List(supportedAddressTypes)))
 	}
diff --git a/pkg/registry/discovery/endpointslice/declarative_validation_test.go b/pkg/registry/discovery/endpointslice/declarative_validation_test.go
index cf4bb110d4e..9c78e9caa06 100644
--- a/pkg/registry/discovery/endpointslice/declarative_validation_test.go
+++ b/pkg/registry/discovery/endpointslice/declarative_validation_test.go
@@ -70,6 +70,12 @@ func testDeclarativeValidate(t *testing.T, apiVersion string) {
 				field.TooMany(field.NewPath("endpoints").Index(0).Child("addresses"), 101, 100).WithOrigin("maxItems"),
 			},
 		},
+		"invalid missing addressType": {
+			input: mkValidEndpointSlice(tweakAddressType("")),
+			expectedErrs: field.ErrorList{
+				field.Required(field.NewPath("addressType"), ""),
+			},
+		},
 	}
 	for name, tc := range testCases {
 		t.Run(name, func(t *testing.T) {
@@ -164,3 +170,9 @@ func tweakAddresses(count int) func(*discovery.EndpointSlice) {
 		obj.Endpoints[0].Addresses = addrs
 	}
 }
+
+func tweakAddressType(addrType discovery.AddressType) func(*discovery.EndpointSlice) {
+	return func(obj *discovery.EndpointSlice) {
+		obj.AddressType = addrType
+	}
+}
diff --git a/staging/src/k8s.io/api/discovery/v1/generated.proto b/staging/src/k8s.io/api/discovery/v1/generated.proto
index 7c987d8162f..146865d8fc0 100644
--- a/staging/src/k8s.io/api/discovery/v1/generated.proto
+++ b/staging/src/k8s.io/api/discovery/v1/generated.proto
@@ -184,6 +184,8 @@ message EndpointSlice {
   // The EndpointSlice controller only generates, and kube-proxy only processes,
   // slices of addressType "IPv4" and "IPv6". No semantics are defined for
   // the "FQDN" type.
+  // +required
+  // +k8s:required
   optional string addressType = 4;
 
   // endpoints is a list of unique endpoints in this slice. Each slice may
diff --git a/staging/src/k8s.io/api/discovery/v1/types.go b/staging/src/k8s.io/api/discovery/v1/types.go
index 20b4c43f044..a682a4596df 100644
--- a/staging/src/k8s.io/api/discovery/v1/types.go
+++ b/staging/src/k8s.io/api/discovery/v1/types.go
@@ -48,6 +48,8 @@ type EndpointSlice struct {
 	// The EndpointSlice controller only generates, and kube-proxy only processes,
 	// slices of addressType "IPv4" and "IPv6". No semantics are defined for
 	// the "FQDN" type.
+	// +required
+	// +k8s:required
 	AddressType AddressType `json:"addressType" protobuf:"bytes,4,rep,name=addressType"`
 
 	// endpoints is a list of unique endpoints in this slice. Each slice may
diff --git a/staging/src/k8s.io/api/discovery/v1beta1/generated.proto b/staging/src/k8s.io/api/discovery/v1beta1/generated.proto
index 1de1d5e3c2a..2be880149e1 100644
--- a/staging/src/k8s.io/api/discovery/v1beta1/generated.proto
+++ b/staging/src/k8s.io/api/discovery/v1beta1/generated.proto
@@ -170,6 +170,8 @@ message EndpointSlice {
   // * IPv4: Represents an IPv4 Address.
   // * IPv6: Represents an IPv6 Address.
   // * FQDN: Represents a Fully Qualified Domain Name.
+  // +required
+  // +k8s:required
   optional string addressType = 4;
 
   // endpoints is a list of unique endpoints in this slice. Each slice may
diff --git a/staging/src/k8s.io/api/discovery/v1beta1/types.go b/staging/src/k8s.io/api/discovery/v1beta1/types.go
index 0f3b403d5ae..fbc65ab5fdf 100644
--- a/staging/src/k8s.io/api/discovery/v1beta1/types.go
+++ b/staging/src/k8s.io/api/discovery/v1beta1/types.go
@@ -45,6 +45,8 @@ type EndpointSlice struct {
 	// * IPv4: Represents an IPv4 Address.
 	// * IPv6: Represents an IPv6 Address.
 	// * FQDN: Represents a Fully Qualified Domain Name.
+	// +required
+	// +k8s:required
 	AddressType AddressType `json:"addressType" protobuf:"bytes,4,rep,name=addressType"`
 
 	// endpoints is a list of unique endpoints in this slice. Each slice may