diff --git a/src/Nimiq/Signer.cpp b/src/Nimiq/Signer.cpp
index ed08cefdff3..e8de7375c62 100644
--- a/src/Nimiq/Signer.cpp
+++ b/src/Nimiq/Signer.cpp
@@ -19,7 +19,8 @@ Proto::SigningOutput Signer::sign(const Proto::SigningInput& input) noexcept {
         /* destination */Address(input.destination()),
         /* amount */input.value(),
         /* fee */input.fee(),
-        /* vsh */input.validity_start_height()
+        /* vsh */input.validity_start_height(),
+        /* networkId */input.network_id()
     );
 
     auto signer = Signer();
diff --git a/src/Nimiq/Transaction.cpp b/src/Nimiq/Transaction.cpp
index e5ba42006fe..9617cd2fcbb 100644
--- a/src/Nimiq/Transaction.cpp
+++ b/src/Nimiq/Transaction.cpp
@@ -9,25 +9,33 @@
 
 namespace TW::Nimiq {
 
-const uint8_t NETWORK_ID = 42;
 const uint8_t EMPTY_FLAGS = 0;
 
 std::vector<uint8_t> Transaction::serialize() const {
+    // Source code:
+    // https://github.com/nimiq/core-rs-albatross/blame/b8ed402c9096ffb54afea52347b91ab7831e75de/primitives/transaction/src/lib.rs#L699
+
     std::vector<uint8_t> data;
 
     data.push_back(0x00); // Basic TX type
+    if (isAlbatross()) {
+        data.push_back(0x00); // Signature Proof type and flags (Ed25519 type and no flags)
+    }
     data.insert(data.end(), sender_pub_key.begin(), sender_pub_key.end());
     data.insert(data.end(), destination.bytes.begin(), destination.bytes.end());
     encode64BE(amount, data);
     encode64BE(fee, data);
     encode32BE(vsh, data);
-    data.push_back(NETWORK_ID);
+    data.push_back(consensusNetworkId());
     data.insert(data.end(), signature.begin(), signature.end());
 
     return data;
 }
 
 std::vector<uint8_t> Transaction::getPreImage() const {
+    // Source code:
+    // https://github.com/nimiq/core-rs-albatross/blame/b8ed402c9096ffb54afea52347b91ab7831e75de/primitives/transaction/src/lib.rs#L582
+
     std::vector<uint8_t> data;
 
     // Build pre-image
@@ -40,10 +48,32 @@ std::vector<uint8_t> Transaction::getPreImage() const {
     encode64BE(amount, data);
     encode64BE(fee, data);
     encode32BE(vsh, data);
-    data.push_back(NETWORK_ID);
+    data.push_back(consensusNetworkId());
     data.push_back(EMPTY_FLAGS);
+    if (isAlbatross()) {
+        data.push_back(0x00); // Sender Data size (+ 0 bytes of data)
+    }
 
     return data;
 }
 
+bool Transaction::isAlbatross() const {
+    if (networkId == Proto::NetworkId::MainnetAlbatross) {
+        return true;
+    }
+    return false;
+}
+
+uint8_t Transaction::consensusNetworkId() const {
+    switch (networkId) {
+        case Proto::NetworkId::UseDefault:
+        case Proto::NetworkId::Mainnet:
+            return static_cast<uint8_t>(Proto::NetworkId::Mainnet);
+        case Proto::NetworkId::MainnetAlbatross:
+            return static_cast<uint8_t>(Proto::NetworkId::MainnetAlbatross);
+        default:
+            throw std::invalid_argument("Invalid network ID");
+    }
+}
+
 } // namespace TW::Nimiq
diff --git a/src/Nimiq/Transaction.h b/src/Nimiq/Transaction.h
index 4615d440537..98ea799387d 100644
--- a/src/Nimiq/Transaction.h
+++ b/src/Nimiq/Transaction.h
@@ -5,6 +5,7 @@
 #pragma once
 
 #include "Address.h"
+#include "proto/Nimiq.pb.h"
 
 namespace TW::Nimiq {
 
@@ -20,16 +21,22 @@ class Transaction {
     uint64_t fee;
     // Validity start (block) height
     uint32_t vsh;
+    // Network ID
+    Proto::NetworkId networkId;
     // Sender signature
     std::array<uint8_t, 64> signature;
 
     Transaction(const std::array<uint8_t, 32>& sender, const Address& dest, uint64_t amount,
-                uint64_t fee, uint32_t vsh)
-        : sender_pub_key(sender), destination(dest), amount(amount), fee(fee), vsh(vsh) {}
+                uint64_t fee, uint32_t vsh, Proto::NetworkId networkId)
+        : sender_pub_key(sender), destination(dest), amount(amount), fee(fee), vsh(vsh), networkId(networkId) {}
 
   public:
     std::vector<uint8_t> serialize() const;
     std::vector<uint8_t> getPreImage() const;
+
+  private:
+    bool isAlbatross() const;
+    uint8_t consensusNetworkId() const;
 };
 
 } // namespace TW::Nimiq
diff --git a/src/proto/Nimiq.proto b/src/proto/Nimiq.proto
index 76d00dd903e..13abbd9c734 100644
--- a/src/proto/Nimiq.proto
+++ b/src/proto/Nimiq.proto
@@ -3,6 +3,14 @@ syntax = "proto3";
 package TW.Nimiq.Proto;
 option java_package = "wallet.core.jni.proto";
 
+enum NetworkId {
+    UseDefault = 0;
+    // Default PoW Mainnet.
+    Mainnet = 42;
+    // PoS Mainnet starting at the PoW block height 3’456’000.
+    MainnetAlbatross = 24;
+}
+
 // Input data necessary to create a signed transaction.
 message SigningInput {
     // The secret private key used for signing (32 bytes).
@@ -19,6 +27,9 @@ message SigningInput {
 
     // Validity start, in block height
     uint32 validity_start_height = 5;
+
+    // Network ID.
+    NetworkId network_id = 6;
 }
 
 // Result containing the signed and encoded transaction.
diff --git a/swift/Tests/Blockchains/NimiqTests.swift b/swift/Tests/Blockchains/NimiqTests.swift
index 8ee8dac51ed..d96ad33e5ce 100644
--- a/swift/Tests/Blockchains/NimiqTests.swift
+++ b/swift/Tests/Blockchains/NimiqTests.swift
@@ -14,10 +14,11 @@ class NimiqTests: XCTestCase {
             $0.value = 42042042
             $0.fee = 1000
             $0.validityStartHeight = 314159
+            $0.networkID = .mainnetAlbatross
         }
 
         let output: NimiqSigningOutput = AnySigner.sign(input: input, coin: .nimiq)
 
-        XCTAssertEqual(output.encoded.hexString, "0070c7492aaa9c9ac7a05bc0d9c5db2dae9372029654f71f0c7f95deed5099b7021450ffc385cd4e7c6ac9a7e91614ca67ff90568a00000000028182ba00000000000003e80004cb2f2a74dc7f6e0ab58a0bf52cc6e8801b0cca132dd4229d9a3e3a3d2f90e4d8f045d981b771bf5fc3851a98f3c617b1a943228f963e910e061808a721cfa0e3cad50b")
+        XCTAssertEqual(output.encoded.hexString, "000070c7492aaa9c9ac7a05bc0d9c5db2dae9372029654f71f0c7f95deed5099b7021450ffc385cd4e7c6ac9a7e91614ca67ff90568a00000000028182ba00000000000003e80004cb2f180ba678744be3bf9cd44fbcdabfb5be209f21739934836e26055610ab02720fa99489219d9f3581664473a1b40b30ad1f6e13150d59f8234a42c3f0de3d505405")
     }
 }
diff --git a/tests/chains/Nimiq/SignerTests.cpp b/tests/chains/Nimiq/SignerTests.cpp
index c22441f2f39..d8a56bdb9cd 100644
--- a/tests/chains/Nimiq/SignerTests.cpp
+++ b/tests/chains/Nimiq/SignerTests.cpp
@@ -30,7 +30,8 @@ TEST(NimiqSigner, Sign) {
         Address("NQ86 2H8F YGU5 RM77 QSN9 LYLH C56A CYYR 0MLA"),
         42042042,
         1000,
-        314159
+        314159,
+        Proto::NetworkId::Mainnet
     );
 
     Signer signer;
diff --git a/tests/chains/Nimiq/TWAnySignerTests.cpp b/tests/chains/Nimiq/TWAnySignerTests.cpp
index a618b1ac04f..f8879960cd1 100644
--- a/tests/chains/Nimiq/TWAnySignerTests.cpp
+++ b/tests/chains/Nimiq/TWAnySignerTests.cpp
@@ -28,4 +28,22 @@ TEST(TWAnySignerNimiq, Sign) {
     EXPECT_EQ(hex(output.encoded()), "0070c7492aaa9c9ac7a05bc0d9c5db2dae9372029654f71f0c7f95deed5099b7021450ffc385cd4e7c6ac9a7e91614ca67ff90568a00000000028182ba00000000000003e80004cb2f2a74dc7f6e0ab58a0bf52cc6e8801b0cca132dd4229d9a3e3a3d2f90e4d8f045d981b771bf5fc3851a98f3c617b1a943228f963e910e061808a721cfa0e3cad50b");
 }
 
+TEST(TWAnySignerNimiq, SignPoS) {
+    auto privateKey = parse_hex("e3cc33575834add098f8487123cd4bca543ee859b3e8cfe624e7e6a97202b756");
+
+    Proto::SigningInput input;
+
+    input.set_destination("NQ86 2H8F YGU5 RM77 QSN9 LYLH C56A CYYR 0MLA");
+    input.set_fee(1000);
+    input.set_value(42042042);
+    input.set_validity_start_height(314159);
+    input.set_private_key(privateKey.data(), privateKey.size());
+    input.set_network_id(Proto::NetworkId::MainnetAlbatross);
+
+    Proto::SigningOutput output;
+    ANY_SIGN(input, TWCoinTypeNimiq);
+
+    EXPECT_EQ(hex(output.encoded()), "000070c7492aaa9c9ac7a05bc0d9c5db2dae9372029654f71f0c7f95deed5099b7021450ffc385cd4e7c6ac9a7e91614ca67ff90568a00000000028182ba00000000000003e80004cb2f180ba678744be3bf9cd44fbcdabfb5be209f21739934836e26055610ab02720fa99489219d9f3581664473a1b40b30ad1f6e13150d59f8234a42c3f0de3d505405");
+}
+
 } // namespace TW::Nimiq::tests
diff --git a/tests/chains/Nimiq/TransactionTests.cpp b/tests/chains/Nimiq/TransactionTests.cpp
index 679f955f4ca..cd6eaeb2b22 100644
--- a/tests/chains/Nimiq/TransactionTests.cpp
+++ b/tests/chains/Nimiq/TransactionTests.cpp
@@ -22,7 +22,8 @@ TEST(NimiqTransaction, PreImage) {
         Address("NQ86 2H8F YGU5 RM77 QSN9 LYLH C56A CYYR 0MLA"),
         42042042,
         1000,
-        314159
+        314159,
+        Proto::NetworkId::UseDefault
     );
     ASSERT_EQ(hex(tx.getPreImage()),
         "000082d5f776378ccbe34a3d941f22d4715bc9f81e0d001450ffc385cd4e7c6ac9a7e91614ca67ff90568a0000000000028182ba00000000000003e80004cb2f2a00");
@@ -39,7 +40,8 @@ TEST(NimiqTransaction, Serialize) {
         Address("NQ86 2H8F YGU5 RM77 QSN9 LYLH C56A CYYR 0MLA"),
         42042042,
         1000,
-        314159
+        314159,
+        Proto::NetworkId::Mainnet
     );
 
     const auto signature = parse_hex("74dc7f6e0ab58a0bf52cc6e8801b0cca132dd4229d9a3e3a3d2f90e4d8f045d981b771bf5fc3851a98f3c617b1a943228f963e910e061808a721cfa0e3cad50b");