Yes, you can exchange on weekends and holidays.
USD：BUY ¥155.99/SELL ¥151.70
EUR：BUY ¥164.50/SELL ¥160.00
GBP：BUY ¥200.30/SELL ¥186.80
CNY：BUY ¥22.38/SELL ¥19.65
HKD：BUY ¥20.96/SELL ¥18.50
KRW：BUY ¥0.1225/SELL ¥0.0973
PHP：BUY ¥2.91/SELL ¥2.32
SGD：BUY ¥118.56/SELL ¥111.00
THB：BUY ¥4.90/SELL ¥4.05
CAD：BUY ¥113.59/SELL ¥104.95
AUD：BUY ¥105.16/SELL ¥93.19
NZD：BUY ¥95.46/SELL ¥85.07
CHF：BUY ¥177.98/SELL ¥171.09
TWD：BUY ¥5.20/SELL ¥4.31
MYR：BUY ¥38.89/SELL ¥30.69
VND：BUY ¥0.01/SELL ¥0.005