diff --git a/lib/rdf/xsd/datatypes/date.ex b/lib/rdf/xsd/datatypes/date.ex
index aa689dd..2f73c29 100644
--- a/lib/rdf/xsd/datatypes/date.ex
+++ b/lib/rdf/xsd/datatypes/date.ex
@@ -16,8 +16,16 @@ defmodule RDF.XSD.Date do
   alias RDF.XSD
 
 
+  def_applicable_facet XSD.Facets.ExplicitTimezone
   def_applicable_facet XSD.Facets.Pattern
 
+  @doc false
+  def explicit_timezone_conform?(:required, {_, _}, _), do: true
+  def explicit_timezone_conform?(:required, _, _), do: false
+  def explicit_timezone_conform?(:prohibited, {_, _}, _), do: false
+  def explicit_timezone_conform?(:prohibited, _, _), do: true
+  def explicit_timezone_conform?(:optional, _, _), do: true
+
   @doc false
   def pattern_conform?(pattern, _value, lexical) do
     XSD.Facets.Pattern.conform?(pattern, lexical)
diff --git a/lib/rdf/xsd/datatypes/date_time.ex b/lib/rdf/xsd/datatypes/date_time.ex
index f0cb811..506ec6f 100644
--- a/lib/rdf/xsd/datatypes/date_time.ex
+++ b/lib/rdf/xsd/datatypes/date_time.ex
@@ -12,8 +12,16 @@ defmodule RDF.XSD.DateTime do
   alias RDF.XSD
 
 
+  def_applicable_facet XSD.Facets.ExplicitTimezone
   def_applicable_facet XSD.Facets.Pattern
 
+  @doc false
+  def explicit_timezone_conform?(:required, %DateTime{}, _), do: true
+  def explicit_timezone_conform?(:required, _, _), do: false
+  def explicit_timezone_conform?(:prohibited, %NaiveDateTime{}, _), do: true
+  def explicit_timezone_conform?(:prohibited, _, _), do: false
+  def explicit_timezone_conform?(:optional, _, _), do: true
+
   @doc false
   def pattern_conform?(pattern, _value, lexical) do
     XSD.Facets.Pattern.conform?(pattern, lexical)
diff --git a/lib/rdf/xsd/datatypes/time.ex b/lib/rdf/xsd/datatypes/time.ex
index 5aa1999..f5d61d6 100644
--- a/lib/rdf/xsd/datatypes/time.ex
+++ b/lib/rdf/xsd/datatypes/time.ex
@@ -16,8 +16,16 @@ defmodule RDF.XSD.Time do
   @tz_number_grammar ~r/\A(?:([\+\-])(\d{2}):(\d{2}))\Z/
 
 
+  def_applicable_facet XSD.Facets.ExplicitTimezone
   def_applicable_facet XSD.Facets.Pattern
 
+  @doc false
+  def explicit_timezone_conform?(:required, {_, true}, _), do: true
+  def explicit_timezone_conform?(:required, _, _), do: false
+  def explicit_timezone_conform?(:prohibited, {_, true}, _), do: false
+  def explicit_timezone_conform?(:prohibited, _, _), do: true
+  def explicit_timezone_conform?(:optional, _, _), do: true
+
   @doc false
   def pattern_conform?(pattern, _value, lexical) do
     XSD.Facets.Pattern.conform?(pattern, lexical)
diff --git a/lib/rdf/xsd/facets/explicit_timezone.ex b/lib/rdf/xsd/facets/explicit_timezone.ex
new file mode 100644
index 0000000..54eee0f
--- /dev/null
+++ b/lib/rdf/xsd/facets/explicit_timezone.ex
@@ -0,0 +1,5 @@
+defmodule RDF.XSD.Facets.ExplicitTimezone do
+  @type t :: :required | :prohibited | :optional
+
+  use RDF.XSD.Facet, name: :explicit_timezone, type: t
+end
diff --git a/test/support/test_datatypes.ex b/test/support/test_datatypes.ex
index ae68bc5..b51fba2 100644
--- a/test/support/test_datatypes.ex
+++ b/test/support/test_datatypes.ex
@@ -67,4 +67,31 @@ defmodule RDF.TestDatatypes do
     def_facet_constraint RDF.XSD.Facets.MinInclusive, 0
     def_facet_constraint RDF.XSD.Facets.MaxInclusive, 1
   end
+
+  defmodule DateTimeWithTz do
+    use RDF.XSD.Datatype.Restriction,
+        name: "datetime_with_tz",
+        id: "http://example.com/datetime-with-tz",
+        base: RDF.XSD.DateTime
+
+    def_facet_constraint RDF.XSD.Facets.ExplicitTimezone, :required
+  end
+
+  defmodule DateWithoutTz do
+    use RDF.XSD.Datatype.Restriction,
+        name: "date_with_tz",
+        id: "http://example.com/date-with-tz",
+        base: RDF.XSD.Date
+
+    def_facet_constraint RDF.XSD.Facets.ExplicitTimezone, :prohibited
+  end
+
+  defmodule CustomTime do
+    use RDF.XSD.Datatype.Restriction,
+        name: "time_with_tz",
+        id: "http://example.com/time-with-tz",
+        base: RDF.XSD.Time
+
+    def_facet_constraint RDF.XSD.Facets.ExplicitTimezone, :optional
+  end
 end
diff --git a/test/unit/xsd/datatypes/date_test.exs b/test/unit/xsd/datatypes/date_test.exs
index a04f357..397b1e7 100644
--- a/test/unit/xsd/datatypes/date_test.exs
+++ b/test/unit/xsd/datatypes/date_test.exs
@@ -4,9 +4,11 @@ defmodule RDF.XSD.DateTest do
     name: "date",
     primitive: true,
     applicable_facets: [
+      RDF.XSD.Facets.ExplicitTimezone,
       RDF.XSD.Facets.Pattern
     ],
     facets: %{
+      explicit_timezone: nil,
       pattern: nil
     },
     valid: %{
diff --git a/test/unit/xsd/datatypes/date_time_test.exs b/test/unit/xsd/datatypes/date_time_test.exs
index 3470030..a0fd72a 100644
--- a/test/unit/xsd/datatypes/date_time_test.exs
+++ b/test/unit/xsd/datatypes/date_time_test.exs
@@ -6,9 +6,11 @@ defmodule RDF.XSD.DateTimeTest do
     name: "dateTime",
     primitive: true,
     applicable_facets: [
+      RDF.XSD.Facets.ExplicitTimezone,
       RDF.XSD.Facets.Pattern
     ],
     facets: %{
+      explicit_timezone: nil,
       pattern: nil
     },
     valid: %{
diff --git a/test/unit/xsd/datatypes/time_test.exs b/test/unit/xsd/datatypes/time_test.exs
index b8eb44c..232b503 100644
--- a/test/unit/xsd/datatypes/time_test.exs
+++ b/test/unit/xsd/datatypes/time_test.exs
@@ -4,9 +4,11 @@ defmodule RDF.XSD.TimeTest do
     name: "time",
     primitive: true,
     applicable_facets: [
+      RDF.XSD.Facets.ExplicitTimezone,
       RDF.XSD.Facets.Pattern
     ],
     facets: %{
+      explicit_timezone: nil,
       pattern: nil
     },
     valid: %{
diff --git a/test/unit/xsd/facets/explicit_timezone_test.exs b/test/unit/xsd/facets/explicit_timezone_test.exs
new file mode 100644
index 0000000..b77eece
--- /dev/null
+++ b/test/unit/xsd/facets/explicit_timezone_test.exs
@@ -0,0 +1,26 @@
+defmodule RDF.XSD.Facets.ExplicitTimezoneTest do
+  use RDF.Test.Case
+
+  import RDF.XSD.Datatype.Test.Case, only: [dt: 1]
+
+  alias RDF.TestDatatypes.{DateTimeWithTz, DateWithoutTz, CustomTime}
+
+  test "DateTimeWithTz" do
+    assert DateTimeWithTz.new(dt("2010-01-01T00:00:00Z")) |> RDF.Literal.valid?()
+    assert DateTimeWithTz.new("2010-01-01T00:00:00Z") |> RDF.Literal.valid?()
+    refute DateTimeWithTz.new(~N[2010-01-01T00:00:00]) |> RDF.Literal.valid?()
+    refute DateTimeWithTz.new("2010-01-01T00:00:00") |> RDF.Literal.valid?()
+  end
+
+  test "DateWithoutTz" do
+    assert DateWithoutTz.new(~D[2010-01-01]) |> RDF.Literal.valid?()
+    assert DateWithoutTz.new("2010-01-01") |> RDF.Literal.valid?()
+    refute DateWithoutTz.new("2010-01-01Z") |> RDF.Literal.valid?()
+  end
+
+  test "CustomTime" do
+    assert CustomTime.new(~T[00:00:00] ) |> RDF.Literal.valid?()
+    assert CustomTime.new("00:00:00Z") |> RDF.Literal.valid?()
+    assert CustomTime.new("00:00:00") |> RDF.Literal.valid?()
+  end
+end