Yes, you can exchange on weekends and holidays.
USD：BUY ¥155.38/SELL ¥151.05
EUR：BUY ¥178.78/SELL ¥174.15
GBP：BUY ¥207.21/SELL ¥194.35
CNY：BUY ¥22.73/SELL ¥20.13
HKD：BUY ¥20.91/SELL ¥18.51
KRW：BUY ¥0.1188/SELL ¥0.0939
PHP：BUY ¥2.91/SELL ¥2.32
SGD：BUY ¥121.05/SELL ¥113.96
THB：BUY ¥5.10/SELL ¥4.28
CAD：BUY ¥112.39/SELL ¥103.88
AUD：BUY ¥105.17/SELL ¥93.36
NZD：BUY ¥91.85/SELL ¥81.26
CHF：BUY ¥192.05/SELL ¥185.69
TWD：BUY ¥5.41/SELL ¥4.55
MYR：BUY ¥41.12/SELL ¥32.52
VND：BUY ¥0.01/SELL ¥0.005