diff --git a/contrib/seeds/generate-seeds.py b/contrib/seeds/generate-seeds.py
index e921757802a..c84be1055da 100755
--- a/contrib/seeds/generate-seeds.py
+++ b/contrib/seeds/generate-seeds.py
@@ -115,7 +115,7 @@ def parse_spec(s):
 def ser_compact_size(l):
     r = b""
     if l < 253:
-        r = struct.pack("B", l)
+        r = l.to_bytes(1, "little")
     elif l < 0x10000:
         r = struct.pack("<BH", 253, l)
     elif l < 0x100000000:
@@ -129,10 +129,10 @@ def bip155_serialize(spec):
     Serialize (networkID, addr, port) tuple to BIP155 binary format.
     '''
     r = b""
-    r += struct.pack('B', spec[0].value)
+    r += spec[0].value.to_bytes(1, "little")
     r += ser_compact_size(len(spec[1]))
     r += spec[1]
-    r += struct.pack('>H', spec[2])
+    r += spec[2].to_bytes(2, "big")
     return r
 
 def process_nodes(g, f, structname):
diff --git a/contrib/signet/miner b/contrib/signet/miner
index e5daf9f993e..7b7b3feb39b 100755
--- a/contrib/signet/miner
+++ b/contrib/signet/miner
@@ -52,10 +52,10 @@ def signet_txs(block, challenge):
     mroot = block.get_merkle_root(hashes)
 
     sd = b""
-    sd += struct.pack("<i", block.nVersion)
+    sd += block.nVersion.to_bytes(4, "little", signed=True)
     sd += ser_uint256(block.hashPrevBlock)
     sd += ser_uint256(mroot)
-    sd += struct.pack("<I", block.nTime)
+    sd += block.nTime.to_bytes(4, "little")
 
     to_spend = CTransaction()
     to_spend.nVersion = 0
diff --git a/test/functional/feature_addrman.py b/test/functional/feature_addrman.py
index c17b697ec1e..f422673f6b4 100755
--- a/test/functional/feature_addrman.py
+++ b/test/functional/feature_addrman.py
@@ -28,15 +28,15 @@ def serialize_addrman(
     tried = []
     INCOMPATIBILITY_BASE = 32
     r = MAGIC_BYTES[net_magic]
-    r += struct.pack("B", format)
-    r += struct.pack("B", (INCOMPATIBILITY_BASE + lowest_compatible))
+    r += format.to_bytes(1, "little")
+    r += (INCOMPATIBILITY_BASE + lowest_compatible).to_bytes(1, "little")
     r += ser_uint256(bucket_key)
-    r += struct.pack("<i", (len_new or len(new)))
-    r += struct.pack("<i", (len_tried or len(tried)))
+    r += (len_new or len(new)).to_bytes(4, "little", signed=True)
+    r += (len_tried or len(tried)).to_bytes(4, "little", signed=True)
     ADDRMAN_NEW_BUCKET_COUNT = 1 << 10
-    r += struct.pack("<i", (ADDRMAN_NEW_BUCKET_COUNT ^ (1 << 30)))
+    r += (ADDRMAN_NEW_BUCKET_COUNT ^ (1 << 30)).to_bytes(4, "little", signed=True)
     for _ in range(ADDRMAN_NEW_BUCKET_COUNT):
-        r += struct.pack("<i", (0))
+        r += (0).to_bytes(4, "little", signed=True)
     checksum = hash256(r)
     r += mock_checksum or checksum
     return r
diff --git a/test/functional/p2p_segwit.py b/test/functional/p2p_segwit.py
index 45bbd7f1c30..03a19be722f 100755
--- a/test/functional/p2p_segwit.py
+++ b/test/functional/p2p_segwit.py
@@ -1165,16 +1165,16 @@ class SegWitTest(BitcoinTestFramework):
                 if not self.wit.is_null():
                     flags |= 1
                 r = b""
-                r += struct.pack("<i", self.nVersion)
+                r += self.nVersion.to_bytes(4, "little", signed=True)
                 if flags:
                     dummy = []
                     r += ser_vector(dummy)
-                    r += struct.pack("<B", flags)
+                    r += flags.to_bytes(1, "little")
                 r += ser_vector(self.vin)
                 r += ser_vector(self.vout)
                 if flags & 1:
                     r += self.wit.serialize()
-                r += struct.pack("<I", self.nLockTime)
+                r += self.nLockTime.to_bytes(4, "little")
                 return r
 
         tx2 = BrokenCTransaction()
@@ -1976,11 +1976,11 @@ class SegWitTest(BitcoinTestFramework):
         def serialize_with_bogus_witness(tx):
             flags = 3
             r = b""
-            r += struct.pack("<i", tx.nVersion)
+            r += tx.nVersion.to_bytes(4, "little", signed=True)
             if flags:
                 dummy = []
                 r += ser_vector(dummy)
-                r += struct.pack("<B", flags)
+                r += flags.to_bytes(1, "little")
             r += ser_vector(tx.vin)
             r += ser_vector(tx.vout)
             if flags & 1:
@@ -1990,7 +1990,7 @@ class SegWitTest(BitcoinTestFramework):
                     for _ in range(len(tx.wit.vtxinwit), len(tx.vin)):
                         tx.wit.vtxinwit.append(CTxInWitness())
                 r += tx.wit.serialize()
-            r += struct.pack("<I", tx.nLockTime)
+            r += tx.nLockTime.to_bytes(4, "little")
             return r
 
         class msg_bogus_tx(msg_tx):
diff --git a/test/functional/test_framework/p2p.py b/test/functional/test_framework/p2p.py
index 00bd1e4017a..4b846df94a4 100755
--- a/test/functional/test_framework/p2p.py
+++ b/test/functional/test_framework/p2p.py
@@ -411,7 +411,7 @@ class P2PConnection(asyncio.Protocol):
             tmsg = self.magic_bytes
             tmsg += msgtype
             tmsg += b"\x00" * (12 - len(msgtype))
-            tmsg += struct.pack("<I", len(data))
+            tmsg += len(data).to_bytes(4, "little")
             th = sha256(data)
             h = sha256(th)
             tmsg += h[:4]
diff --git a/test/functional/test_framework/script.py b/test/functional/test_framework/script.py
index 5d6f65b83df..4bf598ca153 100644
--- a/test/functional/test_framework/script.py
+++ b/test/functional/test_framework/script.py
@@ -58,9 +58,9 @@ class CScriptOp(int):
         elif len(d) <= 0xff:
             return b'\x4c' + bytes([len(d)]) + d  # OP_PUSHDATA1
         elif len(d) <= 0xffff:
-            return b'\x4d' + struct.pack('<H', len(d)) + d  # OP_PUSHDATA2
+            return b'\x4d' + len(d).to_bytes(2, "little") + d  # OP_PUSHDATA2
         elif len(d) <= 0xffffffff:
-            return b'\x4e' + struct.pack('<I', len(d)) + d  # OP_PUSHDATA4
+            return b'\x4e' + len(d).to_bytes(4, "little") + d  # OP_PUSHDATA4
         else:
             raise ValueError("Data too long to encode in a PUSHDATA op")
 
@@ -670,7 +670,7 @@ def LegacySignatureMsg(script, txTo, inIdx, hashtype):
         txtmp.vin.append(tmp)
 
     s = txtmp.serialize_without_witness()
-    s += struct.pack("<I", hashtype)
+    s += hashtype.to_bytes(4, "little")
 
     return (s, None)
 
@@ -726,7 +726,7 @@ def SegwitV0SignatureMsg(script, txTo, inIdx, hashtype, amount):
     if (not (hashtype & SIGHASH_ANYONECANPAY) and (hashtype & 0x1f) != SIGHASH_SINGLE and (hashtype & 0x1f) != SIGHASH_NONE):
         serialize_sequence = bytes()
         for i in txTo.vin:
-            serialize_sequence += struct.pack("<I", i.nSequence)
+            serialize_sequence += i.nSequence.to_bytes(4, "little")
         hashSequence = uint256_from_str(hash256(serialize_sequence))
 
     if ((hashtype & 0x1f) != SIGHASH_SINGLE and (hashtype & 0x1f) != SIGHASH_NONE):
@@ -739,16 +739,16 @@ def SegwitV0SignatureMsg(script, txTo, inIdx, hashtype, amount):
         hashOutputs = uint256_from_str(hash256(serialize_outputs))
 
     ss = bytes()
-    ss += struct.pack("<i", txTo.nVersion)
+    ss += txTo.nVersion.to_bytes(4, "little", signed=True)
     ss += ser_uint256(hashPrevouts)
     ss += ser_uint256(hashSequence)
     ss += txTo.vin[inIdx].prevout.serialize()
     ss += ser_string(script)
-    ss += struct.pack("<q", amount)
-    ss += struct.pack("<I", txTo.vin[inIdx].nSequence)
+    ss += amount.to_bytes(8, "little", signed=True)
+    ss += txTo.vin[inIdx].nSequence.to_bytes(4, "little")
     ss += ser_uint256(hashOutputs)
     ss += txTo.nLockTime.to_bytes(4, "little")
-    ss += struct.pack("<I", hashtype)
+    ss += hashtype.to_bytes(4, "little")
     return ss
 
 def SegwitV0SignatureHash(*args, **kwargs):
@@ -818,8 +818,8 @@ def TaprootSignatureMsg(txTo, spent_utxos, hash_type, input_index = 0, scriptpat
     in_type = hash_type & SIGHASH_ANYONECANPAY
     spk = spent_utxos[input_index].scriptPubKey
     ss = bytes([0, hash_type]) # epoch, hash_type
-    ss += struct.pack("<i", txTo.nVersion)
-    ss += struct.pack("<I", txTo.nLockTime)
+    ss += txTo.nVersion.to_bytes(4, "little", signed=True)
+    ss += txTo.nLockTime.to_bytes(4, "little")
     if in_type != SIGHASH_ANYONECANPAY:
         ss += BIP341_sha_prevouts(txTo)
         ss += BIP341_sha_amounts(spent_utxos)
@@ -835,11 +835,11 @@ def TaprootSignatureMsg(txTo, spent_utxos, hash_type, input_index = 0, scriptpat
     ss += bytes([spend_type])
     if in_type == SIGHASH_ANYONECANPAY:
         ss += txTo.vin[input_index].prevout.serialize()
-        ss += struct.pack("<q", spent_utxos[input_index].nValue)
+        ss += spent_utxos[input_index].nValue.to_bytes(8, "little", signed=True)
         ss += ser_string(spk)
-        ss += struct.pack("<I", txTo.vin[input_index].nSequence)
+        ss += txTo.vin[input_index].nSequence.to_bytes(4, "little")
     else:
-        ss += struct.pack("<I", input_index)
+        ss += input_index.to_bytes(4, "little")
     if (spend_type & 1):
         ss += sha256(ser_string(annex))
     if out_type == SIGHASH_SINGLE:
@@ -850,7 +850,7 @@ def TaprootSignatureMsg(txTo, spent_utxos, hash_type, input_index = 0, scriptpat
     if (scriptpath):
         ss += TaggedHash("TapLeaf", bytes([leaf_ver]) + ser_string(script))
         ss += bytes([0])
-        ss += struct.pack("<i", codeseparator_pos)
+        ss += codeseparator_pos.to_bytes(4, "little", signed=True)
     assert len(ss) ==  175 - (in_type == SIGHASH_ANYONECANPAY) * 49 - (out_type != SIGHASH_ALL and out_type != SIGHASH_SINGLE) * 32 + (annex is not None) * 32 + scriptpath * 37
     return ss