Yes, you can exchange on weekends and holidays.
USD：BUY ¥158.98/SELL ¥154.55
EUR：BUY ¥178.34/SELL ¥173.70
GBP：BUY ¥213.62/SELL ¥200.47
CNY：BUY ¥24.57/SELL ¥21.96
HKD：BUY ¥21.23/SELL ¥18.87
KRW：BUY ¥0.1291/SELL ¥0.1045
PHP：BUY ¥2.79/SELL ¥2.21
SGD：BUY ¥125.93/SELL ¥118.92
THB：BUY ¥5.06/SELL ¥4.26
CAD：BUY ¥113.56/SELL ¥104.84
AUD：BUY ¥114.21/SELL ¥102.98
NZD：BUY ¥92.70/SELL ¥81.76
CHF：BUY ¥191.54/SELL ¥185.08
TWD：BUY ¥5.39/SELL ¥4.52
MYR：BUY ¥43.38/SELL ¥34.24
VND：BUY ¥0.01/SELL ¥0.004