Short answer
In many jurisdictions it is: swapping token A for token B is often treated as selling A, even if you never touched dollars. Confirm the rules where you live.
A common misunderstanding is that tax only applies when you cash out to your bank. In many places, including the US and UK, exchanging one crypto asset for another is itself a disposal, measured at the value at the time of the swap.
On Solana, most memecoin trades are swaps against SOL, so each buy may be a disposal of SOL and each sell a disposal of the memecoin. That adds up quickly for active traders.
This is general information, not advice. A tax professional can tell you how it applies to you and which tools can help you calculate it.
General information, not tax advice. Rules vary by country and change over time.
See the checks for yourself
18+ only. Self-custodial: you keep your keys. 0.5% per trade, no minimum. Memecoins can go to zero.