Main pick

MEXC
Altcoin-first Sui route
MEXC is the strongest first route when SUI is part of a broader new-coin search and coin breadth matters immediately.
SUI

If you are searching where to buy Sui, do not let a newer-coin search turn into a giant exchange loop. Start with MEXC as the broader-access route, keep Binance as the mainstream backup, and only use a third path if you already know workflow matters more.
Coin snapshot
Start here
Pick one default and one backup instead of reopening the full exchange search.
Main pick

Altcoin-first Sui route
MEXC is the strongest first route when SUI is part of a broader new-coin search and coin breadth matters immediately.
Backup

Mainstream backup route
Binance is the right backup when you still want SUI but prefer to benchmark the choice against a larger, more familiar exchange route.
Need one more route?
On this site, MEXC is the altcoin-first route and Binance is the mainstream backup. If you still want a more trading-led route, compare Bybit against MEXC before signing up.
Because SUI intent often overlaps with broader newer-coin intent. An altcoin-first route is usually the most practical first check before you benchmark it against a larger exchange.