diff --git a/stdlib/public/Differentiation/FloatingPointDifferentiation.swift.gyb b/stdlib/public/Differentiation/FloatingPointDifferentiation.swift.gyb
index d1fdf2bb52cf5..8de2cd5ca2a5b 100644
--- a/stdlib/public/Differentiation/FloatingPointDifferentiation.swift.gyb
+++ b/stdlib/public/Differentiation/FloatingPointDifferentiation.swift.gyb
@@ -21,13 +21,16 @@ bits = self_type.bits
 
 def Availability(bits):
     if bits == 16:
-        return '@available(macOS 10.16, iOS 14.0, tvOS 14.0, watchOS 7.0, *)'
+        return '@available(iOS 14.0, tvOS 14.0, watchOS 7.0, *)'
     return ''
 }%
 
 % if bits == 80:
 #if !(os(Windows) || os(Android)) && (arch(i386) || arch(x86_64))
 % end
+% if bits == 16:
+#if !os(macOS) && !(os(iOS) && targetEnvironment(macCatalyst))
+% end
 
 //===----------------------------------------------------------------------===//
 // Protocol conformances
@@ -253,7 +256,7 @@ extension ${Self} {
   }
 }
 
-% if bits == 80:
+% if bits == 80 or bits == 16:
 #endif
 % end
 % end
diff --git a/stdlib/public/core/CTypes.swift b/stdlib/public/core/CTypes.swift
index b1f2432f29adb..a07d756b3f17c 100644
--- a/stdlib/public/core/CTypes.swift
+++ b/stdlib/public/core/CTypes.swift
@@ -57,7 +57,9 @@ public typealias CLong = Int
 public typealias CLongLong = Int64
 
 /// The C '_Float16' type.
-@available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(macOS, unavailable)
+@available(macCatalyst, unavailable)
 public typealias CFloat16 = Float16
 
 /// The C 'float' type.
diff --git a/stdlib/public/core/Codable.swift b/stdlib/public/core/Codable.swift
index f9e66c553bc96..3c9d02bcd839f 100644
--- a/stdlib/public/core/Codable.swift
+++ b/stdlib/public/core/Codable.swift
@@ -4730,7 +4730,9 @@ extension RawRepresentable where RawValue == Float, Self: Decodable {
   }
 }
 
-@available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(macOS, unavailable)
+@available(macCatalyst, unavailable)
 extension Float16: Codable {
   /// Creates a new instance by decoding from the given decoder.
   ///
diff --git a/stdlib/public/core/FloatingPointParsing.swift.gyb b/stdlib/public/core/FloatingPointParsing.swift.gyb
index 5b8aa99c20760..aa58f864ddc42 100644
--- a/stdlib/public/core/FloatingPointParsing.swift.gyb
+++ b/stdlib/public/core/FloatingPointParsing.swift.gyb
@@ -46,7 +46,9 @@ internal func _isspace_clocale(_ u: UTF16.CodeUnit) -> Bool {
 
 //===--- Parsing ----------------------------------------------------------===//
 %if bits == 16:
-@available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(macOS, unavailable)
+@available(macCatalyst, unavailable)
 %end
 extension ${Self}: LosslessStringConvertible {
   /// Creates a new instance from the given string.
diff --git a/stdlib/public/core/FloatingPointTypes.swift.gyb b/stdlib/public/core/FloatingPointTypes.swift.gyb
index f0af6af778043..59a3a0379d2a8 100644
--- a/stdlib/public/core/FloatingPointTypes.swift.gyb
+++ b/stdlib/public/core/FloatingPointTypes.swift.gyb
@@ -40,7 +40,7 @@ RawSignificand = 'UInt' + str(SignificandSize)
 
 def Availability(bits):
     if bits == 16:
-        return '@available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)'
+        return '@available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)\n@available(macOS, unavailable)\n@available(macCatalyst, unavailable)'
     return ''
 
 if Self == 'Float16':
diff --git a/stdlib/public/core/IntegerTypes.swift.gyb b/stdlib/public/core/IntegerTypes.swift.gyb
index 83c61552efae7..0714657e9ebdd 100644
--- a/stdlib/public/core/IntegerTypes.swift.gyb
+++ b/stdlib/public/core/IntegerTypes.swift.gyb
@@ -1152,7 +1152,9 @@ public struct ${Self}
   ///   `source` must be representable in this type after rounding toward
   ///   zero.
 %     if FloatType == 'Float16':
-  @available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+  @available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+  @available(macOS, unavailable)
+  @available(macCatalyst, unavailable)
 %     end
   @_transparent
   public init(_ source: ${FloatType}) {
@@ -1182,7 +1184,9 @@ public struct ${Self}
   ///
   /// - Parameter source: A floating-point value to convert to an integer.
 %     if FloatType == 'Float16':
-  @available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+  @available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+  @available(macOS, unavailable)
+  @available(macCatalyst, unavailable)
 %     end
   @_transparent
   public init?(exactly source: ${FloatType}) {
diff --git a/stdlib/public/core/Runtime.swift b/stdlib/public/core/Runtime.swift
index 236953378fe33..086588cffc43d 100644
--- a/stdlib/public/core/Runtime.swift
+++ b/stdlib/public/core/Runtime.swift
@@ -303,7 +303,9 @@ internal func _float16ToStringImpl(
   _ debug: Bool
 ) -> Int
 
-@available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(macOS, unavailable)
+@available(macCatalyst, unavailable)
 internal func _float16ToString(
   _ value: Float16,
   debug: Bool
diff --git a/stdlib/public/core/SIMDVectorTypes.swift.gyb b/stdlib/public/core/SIMDVectorTypes.swift.gyb
index 59fab35027b99..0faf4371bc7f7 100644
--- a/stdlib/public/core/SIMDVectorTypes.swift.gyb
+++ b/stdlib/public/core/SIMDVectorTypes.swift.gyb
@@ -254,7 +254,9 @@ extension ${Self}: SIMDScalar {
 
 %for (Self, bits) in [('Float16',16), ('Float',32), ('Double',64)]:
 %if bits == 16:
-@available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(macOS, unavailable)
+@available(macCatalyst, unavailable)
 %end
 extension ${Self} : SIMDScalar {
 
diff --git a/test/ClangImporter/cfuncs_parse.swift b/test/ClangImporter/cfuncs_parse.swift
index d522b9d656c1f..746dce15787b3 100644
--- a/test/ClangImporter/cfuncs_parse.swift
+++ b/test/ClangImporter/cfuncs_parse.swift
@@ -72,7 +72,8 @@ func test_powl() {
 }
 #endif
 
-@available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+#if !os(macOS) && !(os(iOS) && targetEnvironment(macCatalyst))
+@available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
 func test_f16() {
   var x = Float16.zero
   f16ptrfunc(&x)
@@ -80,6 +81,7 @@ func test_f16() {
   f16func(x)
   #endif
 }
+#endif
 
 func test_puts(_ s: String) {
   _ = s.withCString { puts($0) + 32 };
diff --git a/test/stdlib/Inputs/FloatingPointConversion.swift.gyb b/test/stdlib/Inputs/FloatingPointConversion.swift.gyb
index f6f98723b3eb7..7cc1d110a35fe 100644
--- a/test/stdlib/Inputs/FloatingPointConversion.swift.gyb
+++ b/test/stdlib/Inputs/FloatingPointConversion.swift.gyb
@@ -16,6 +16,9 @@ var FloatingPointConversionFailures = TestSuite("FloatingPointToFloatingPointCon
 %   SelfSignificandBits = self_type.bits
 %   Self = self_type.stdlib_name
 
+%  if Self == 'Float16':
+#if !os(macOS) && !(os(iOS) && targetEnvironment(macCatalyst))
+%  end
 %  if Self == 'Float80':
 #if !os(Windows) && (arch(i386) || arch(x86_64))
 %  end
@@ -24,6 +27,9 @@ var FloatingPointConversionFailures = TestSuite("FloatingPointToFloatingPointCon
 %   OtherSignificandBits = other_type.bits
 %   OtherFloat = other_type.stdlib_name
 
+%   if OtherFloat == 'Float16':
+#if !os(macOS) && !(os(iOS) && targetEnvironment(macCatalyst))
+%   end
 %   if OtherFloat == 'Float80':
 #if !os(Windows) && (arch(i386) || arch(x86_64))
 %   end
@@ -31,7 +37,7 @@ var FloatingPointConversionFailures = TestSuite("FloatingPointToFloatingPointCon
 %   if OtherSignificandBits <= SelfSignificandBits:
 
 %    if OtherFloat == 'Float16':
-if #available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
+if #available(iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
 %    end
 FloatingPointConversionTruncations.test("${OtherFloat}To${Self}Conversion")
 
@@ -56,7 +62,7 @@ FloatingPointConversionTruncations.test("${OtherFloat}To${Self}Conversion")
 %   else:
 
 %    if Self == 'Float16':
-if #available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
+if #available(iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
 %    end
 FloatingPointConversionTruncations.test("${OtherFloat}To${Self}Conversion")
   .forEach(in: [
@@ -77,7 +83,7 @@ FloatingPointConversionTruncations.test("${OtherFloat}To${Self}Conversion")
 %   end
 
 %    if 'Float16' in [Self, OtherFloat]:
-if #available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
+if #available(iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
 %    end
 FloatingPointConversionTruncations.test("${OtherFloat}To${Self}Conversion/special") {
   expectEqual( 1.0 as ${Self},   ${Self}(exactly:  1.0 as ${OtherFloat}))
@@ -119,6 +125,9 @@ FloatingPointConversionFailures.test("${OtherFloat}To${Self}Conversion/AlwaysSuc
 }
 %    end
 
+%  if OtherFloat == 'Float16':
+#endif
+%  end
 %   if OtherFloat == 'Float80':
 #endif
 %   end
@@ -138,7 +147,8 @@ _UnimplementedError()
 
 extension ${OtherInt} {
   %    if Self == 'Float16':
-  @available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+  @available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+  @available(macOS, unavailable)
   %    end
   static var _test${Self}Conversion: [(${OtherInt}, ${OtherInt}, ${OtherInt}?)] {
     if bitWidth > ${Self}.significandBitCount + 1 {
@@ -165,7 +175,7 @@ extension ${OtherInt} {
 }
 
 %    if Self == 'Float16':
-if #available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
+if #available(iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
 %    end
 FixedPointConversionTruncations.test("${OtherInt}to${Self}")
   .forEach(in: ${OtherInt}._test${Self}Conversion) {
@@ -187,6 +197,9 @@ FixedPointConversionTruncations.test("${OtherInt}to${Self}")
 
 %  end # for in int_types
 
+%  if Self == 'Float16':
+#endif
+%  end
 %  if Self == 'Float80':
 #endif
 %  end
diff --git a/test/stdlib/PrintFloat.swift.gyb b/test/stdlib/PrintFloat.swift.gyb
index 5a7ce9552421d..8556d875368d9 100644
--- a/test/stdlib/PrintFloat.swift.gyb
+++ b/test/stdlib/PrintFloat.swift.gyb
@@ -345,7 +345,9 @@ let PrintTests = TestSuite("FloatingPointPrinting")
 
 % for FloatType in ['Float16', 'Float', 'Double', 'Float80']:
 % if FloatType == 'Float16':
-@available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(macOS, unavailable)
+@available(macCatalyst, unavailable)
 % end
 % if FloatType == 'Float80':
 #if !os(Windows) && (arch(i386) || arch(x86_64))
@@ -383,7 +385,9 @@ fileprivate func expectDescription(_ expected: String, _ object: ${FloatType},
 //   that is closest (as an infinitely-precise real number) to the original
 //   binary float (interpreted as an infinitely-precise real number).
 % if FloatType == 'Float16':
-@available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@available(macOS, unavailable)
+@available(macCatalyst, unavailable)
 % end
 fileprivate func expectAccurateDescription(_ object: ${FloatType},
   _ message: @autoclosure () -> String = "",
@@ -584,7 +588,8 @@ PrintTests.test("Printable_CDouble") {
   expectDescription("-1.0", CDouble(-1.0))
 }
 
-if #available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
+#if !os(macOS) && !(os(iOS) && targetEnvironment(macCatalyst))
+if #available(iOS 14.0, watchOS 7.0, tvOS 14.0, *) {
 PrintTests.test("Printable_Float16") {
   func asFloat16(_ f: Float16) -> Float16 { return f }
 
@@ -727,6 +732,7 @@ PrintTests.test("Printable_Float16") {
   expectDescription("0.0", asFloat16(0.0000000125))
 }
 }
+#endif
 
 PrintTests.test("Printable_Float") {
   func asFloat32(_ f: Float32) -> Float32 { return f }