diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index 22fef3134f..59f72ae709 100644
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -1051,7 +1051,19 @@ func FreePageAlloc(pp *PageAlloc) {
 //
 // This should not be higher than 0x100*pallocChunkBytes to support
 // mips and mipsle, which only have 31-bit address spaces.
-var BaseChunkIdx = ChunkIdx(chunkIndex(((0xc000*pageAlloc64Bit + 0x100*pageAlloc32Bit) * pallocChunkBytes) + arenaBaseOffset*sys.GoosAix))
+var BaseChunkIdx = func() ChunkIdx {
+	var prefix uintptr
+	if pageAlloc64Bit != 0 {
+		prefix = 0xc000
+	} else {
+		prefix = 0x100
+	}
+	baseAddr := prefix * pallocChunkBytes
+	if sys.GoosAix != 0 {
+		baseAddr += arenaBaseOffset
+	}
+	return ChunkIdx(chunkIndex(baseAddr))
+}()
 
 // PageBase returns an address given a chunk index and a page index
 // relative to that chunk.
diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index f20ded5bf7..c57d8c617d 100644
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -199,15 +199,21 @@ const (
 	// we further limit it to 31 bits.
 	//
 	// On ios/arm64, although 64-bit pointers are presumably
-	// available, pointers are truncated to 33 bits. Furthermore,
-	// only the top 4 GiB of the address space are actually available
-	// to the application, but we allow the whole 33 bits anyway for
-	// simplicity.
-	// TODO(mknyszek): Consider limiting it to 32 bits and using
-	// arenaBaseOffset to offset into the top 4 GiB.
+	// available, pointers are truncated to 33 bits in iOS <14.
+	// Furthermore, only the top 4 GiB of the address space are
+	// actually available to the application. In iOS >=14, more
+	// of the address space is available, and the OS can now
+	// provide addresses outside of those 33 bits. Pick 40 bits
+	// as a reasonable balance between address space usage by the
+	// page allocator, and flexibility for what mmap'd regions
+	// we'll accept for the heap. We can't just move to the full
+	// 48 bits because this uses too much address space for older
+	// iOS versions.
+	// TODO(mknyszek): Once iOS <14 is deprecated, promote ios/arm64
+	// to a 48-bit address space like every other arm64 platform.
 	//
 	// WebAssembly currently has a limit of 4GB linear memory.
-	heapAddrBits = (_64bit*(1-sys.GoarchWasm)*(1-sys.GoosIos*sys.GoarchArm64))*48 + (1-_64bit+sys.GoarchWasm)*(32-(sys.GoarchMips+sys.GoarchMipsle)) + 33*sys.GoosIos*sys.GoarchArm64
+	heapAddrBits = (_64bit*(1-sys.GoarchWasm)*(1-sys.GoosIos*sys.GoarchArm64))*48 + (1-_64bit+sys.GoarchWasm)*(32-(sys.GoarchMips+sys.GoarchMipsle)) + 40*sys.GoosIos*sys.GoarchArm64
 
 	// maxAlloc is the maximum size of an allocation. On 64-bit,
 	// it's theoretically possible to allocate 1<<heapAddrBits bytes. On
diff --git a/src/runtime/mgcscavenge_test.go b/src/runtime/mgcscavenge_test.go
index 250343077f..6ba9b3133b 100644
--- a/src/runtime/mgcscavenge_test.go
+++ b/src/runtime/mgcscavenge_test.go
@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"math/rand"
 	. "runtime"
+	"runtime/internal/sys"
 	"testing"
 )
 
@@ -414,7 +415,9 @@ func TestPageAllocScavenge(t *testing.T) {
 			},
 		},
 	}
-	if PageAlloc64Bit != 0 {
+	// Disable these tests on iOS since we have a small address space.
+	// See #46860.
+	if PageAlloc64Bit != 0 && sys.GoosIos == 0 {
 		tests["ScavAllVeryDiscontiguous"] = setup{
 			beforeAlloc: map[ChunkIdx][]BitRange{
 				BaseChunkIdx:          {},
diff --git a/src/runtime/mpagealloc_32bit.go b/src/runtime/mpagealloc_32bit.go
index 331dadade9..951504fc38 100644
--- a/src/runtime/mpagealloc_32bit.go
+++ b/src/runtime/mpagealloc_32bit.go
@@ -2,19 +2,13 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build 386 arm mips mipsle wasm ios,arm64
+// +build 386 arm mips mipsle wasm
 
 // wasm is a treated as a 32-bit architecture for the purposes of the page
 // allocator, even though it has 64-bit pointers. This is because any wasm
 // pointer always has its top 32 bits as zero, so the effective heap address
 // space is only 2^32 bytes in size (see heapAddrBits).
 
-// ios/arm64 is treated as a 32-bit architecture for the purposes of the
-// page allocator, even though it has 64-bit pointers and a 33-bit address
-// space (see heapAddrBits). The 33 bit address space cannot be rounded up
-// to 64 bits because there are too many summary levels to fit in just 33
-// bits.
-
 package runtime
 
 import "unsafe"
diff --git a/src/runtime/mpagealloc_64bit.go b/src/runtime/mpagealloc_64bit.go
index ffacb46c18..1a2ee05236 100644
--- a/src/runtime/mpagealloc_64bit.go
+++ b/src/runtime/mpagealloc_64bit.go
@@ -2,9 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64 !ios,arm64 mips64 mips64le ppc64 ppc64le riscv64 s390x
-
-// See mpagealloc_32bit.go for why ios/arm64 is excluded here.
+// +build amd64 arm64 mips64 mips64le ppc64 ppc64le riscv64 s390x
 
 package runtime
 
diff --git a/src/runtime/mpagealloc_test.go b/src/runtime/mpagealloc_test.go
index 5d979fa95b..857fc140d8 100644
--- a/src/runtime/mpagealloc_test.go
+++ b/src/runtime/mpagealloc_test.go
@@ -7,6 +7,7 @@ package runtime_test
 import (
 	"fmt"
 	. "runtime"
+	"runtime/internal/sys"
 	"testing"
 )
 
@@ -165,7 +166,9 @@ func TestPageAllocGrow(t *testing.T) {
 			},
 		},
 	}
-	if PageAlloc64Bit != 0 {
+	// Disable these tests on iOS since we have a small address space.
+	// See #46860.
+	if PageAlloc64Bit != 0 && sys.GoosIos == 0 {
 		tests["ExtremelyDiscontiguous"] = test{
 			chunks: []ChunkIdx{
 				BaseChunkIdx,
@@ -571,7 +574,9 @@ func TestPageAllocAlloc(t *testing.T) {
 			},
 		},
 	}
-	if PageAlloc64Bit != 0 {
+	// Disable these tests on iOS since we have a small address space.
+	// See #46860.
+	if PageAlloc64Bit != 0 && sys.GoosIos == 0 {
 		const chunkIdxBigJump = 0x100000 // chunk index offset which translates to O(TiB)
 
 		// This test attempts to trigger a bug wherein we look at unmapped summary
diff --git a/src/runtime/mpagecache_test.go b/src/runtime/mpagecache_test.go
index 2ed0c0aa6a..9cbf0dd7de 100644
--- a/src/runtime/mpagecache_test.go
+++ b/src/runtime/mpagecache_test.go
@@ -7,6 +7,7 @@ package runtime_test
 import (
 	"math/rand"
 	. "runtime"
+	"runtime/internal/sys"
 	"testing"
 )
 
@@ -350,7 +351,9 @@ func TestPageAllocAllocToCache(t *testing.T) {
 			},
 		},
 	}
-	if PageAlloc64Bit != 0 {
+	// Disable these tests on iOS since we have a small address space.
+	// See #46860.
+	if PageAlloc64Bit != 0 && sys.GoosIos == 0 {
 		const chunkIdxBigJump = 0x100000 // chunk index offset which translates to O(TiB)
 
 		// This test is similar to the one with the same name for