Yes, you can exchange on weekends and holidays.
USD：BUY ¥158.48/SELL ¥154.20
EUR：BUY ¥186.78/SELL ¥182.00
GBP：BUY ¥217.72/SELL ¥204.71
CNY：BUY ¥23.69/SELL ¥21.08
HKD：BUY ¥21.24/SELL ¥18.84
KRW：BUY ¥0.1187/SELL ¥0.0937
PHP：BUY ¥2.97/SELL ¥2.39
SGD：BUY ¥126.53/SELL ¥119.10
THB：BUY ¥5.30/SELL ¥4.48
CAD：BUY ¥118.29/SELL ¥109.68
AUD：BUY ¥114.86/SELL ¥103.27
NZD：BUY ¥99.47/SELL ¥89.03
CHF：BUY ¥201.57/SELL ¥195.53
TWD：BUY ¥5.43/SELL ¥4.59
MYR：BUY ¥44.76/SELL ¥35.51
VND：BUY ¥0.01/SELL ¥0.004