Yes, you can exchange on weekends and holidays.
USD：BUY ¥152.98/SELL ¥149.00
EUR：BUY ¥177.98/SELL ¥173.20
GBP：BUY ¥206.05/SELL ¥192.84
CNY：BUY ¥22.40/SELL ¥19.90
HKD：BUY ¥20.62/SELL ¥18.25
KRW：BUY ¥0.1167/SELL ¥0.0917
PHP：BUY ¥2.83/SELL ¥2.26
SGD：BUY ¥120.18/SELL ¥112.96
THB：BUY ¥5.06/SELL ¥4.24
CAD：BUY ¥111.51/SELL ¥102.91
AUD：BUY ¥104.07/SELL ¥92.50
NZD：BUY ¥91.62/SELL ¥81.08
CHF：BUY ¥192.48/SELL ¥186.13
TWD：BUY ¥5.39/SELL ¥4.53
MYR：BUY ¥40.54/SELL ¥32.07
VND：BUY ¥0.01/SELL ¥0.005