你在泰国刷泰铢、你的卡是人民币的 → 泰铢 ≠ 人民币,需要换汇 → 产生货币转换费。反之,如果你的卡本来就是泰铢账户,就不用换、也就没这费。核心:你花的货币 ≠ 你卡的货币,才会有货币转换费。You pay in THB in Thailand but your card settles in CNY → THB ≠ CNY, conversion needed → conversion fee. If your card were a THB account, no conversion and no fee. Core rule: the fee applies when transaction currency ≠ card settlement currency.
走 Visa/万事达通道时,很多非美元货币要先换成美元入账,再从美元换成人民币——换了两次,中间那 1%~1.5% 就是货币转换费。银联直接把当地货币换成人民币,少换一道,通常不收这笔。On Visa/Mastercard rails, many non-USD currencies are first converted to USD, then USD to your home currency — two conversions, and the ~1%–1.5% in between is the conversion fee. UnionPay converts the local currency straight to your home currency, skipping a step and usually waiving it.
能免"货币转换费",但免不了 DCC。所谓全币种卡,是把当地货币直接换成你的本币(不走美元中转),所以省掉那笔约 1.5% 的双重货币转换费——这是它的卖点。但 DCC 是另一回事:它是你在结账时选了"用本国货币付"才触发的,由商户方加价 3%~7%,和你拿什么卡无关。所以即使是全币种卡,结账时也必须选当地货币,否则照样被 DCC。至于境外交易费,则看具体卡的政策(有的全币种卡也免,有的不免)。They avoid the conversion fee, but not DCC. An "all-currency" card converts the local currency directly to your home currency (no USD middle step), so it skips the ~1.5% double-conversion fee — that's its selling point. But DCC is separate: it's triggered when you pick "pay in home currency" at checkout, and the merchant adds 3%–7% regardless of your card. So even with an all-currency card you must still choose local currency, or you'll be DCC'd anyway. The foreign transaction fee depends on the specific card (some all-currency cards waive it, some don't).
→ 用计算器对比银联能省多少→ See how much UnionPay saves
相关:DCC 是什么坑 · 怎么查你的卡是哪种货币。Related: what is DCC · find your card's currency.