user2751: It was definitely on August 24th 2017, but not sure about the block number. Many sources reference block 481,822; but others state 481,824.
Also, even if this was the first block to allow segwit transactions, what was the first very block that contained one of them?

user21496: This is a very old question but probably someone else needs to know the same:
SegWit was activated in block 481824 and that block has two p2wpkh txs:
dfcec48bb8491856c353306ab5febeb7e99e4d783eedf3de98f3ee0812b92bad in block 0000000000000000001c8018d9cb3b742ef25114f27563e3fc4a1902167f9893
f91d0a8a78462bc59398f2c5d7a84fcff491c26ba54c4833478b202796c8aafd in block 0000000000000000001c8018d9cb3b742ef25114f27563e3fc4a1902167f9893

I have to run my script against testnet in order to find the best p2wpk tx.

2751: <p>It was definitely on August 24th 2017, but not sure about the block number. Many sources reference block 481,822; but others state 481,824.</p>

<p>Also, even if this was the first block to allow segwit transactions, what was the first very block that contained one of them?</p>
 21496: <p>This is a very old question but probably someone else needs to know the same:</p>

<p>SegWit was activated in block 481824 and that block has two p2wpkh txs:</p>

<pre><code>dfcec48bb8491856c353306ab5febeb7e99e4d783eedf3de98f3ee0812b92bad in block 0000000000000000001c8018d9cb3b742ef25114f27563e3fc4a1902167f9893
f91d0a8a78462bc59398f2c5d7a84fcff491c26ba54c4833478b202796c8aafd in block 0000000000000000001c8018d9cb3b742ef25114f27563e3fc4a1902167f9893
</code></pre>

<p>I have to run my script against testnet in order to find the best p2wpk tx.</p>
