Yes, you can exchange on weekends and holidays.
USD：BUY ¥160.18/SELL ¥156.00
EUR：BUY ¥185.78/SELL ¥181.22
GBP：BUY ¥217.81/SELL ¥205.29
CNY：BUY ¥24.43/SELL ¥21.85
HKD：BUY ¥21.37/SELL ¥19.05
KRW：BUY ¥0.1165/SELL ¥0.0917
PHP：BUY ¥1.85/SELL ¥1.26
SGD：BUY ¥126.71/SELL ¥119.73
THB：BUY ¥5.20/SELL ¥4.38
CAD：BUY ¥118.09/SELL ¥109.66
AUD：BUY ¥117.43/SELL ¥106.00
NZD：BUY ¥97.65/SELL ¥87.31
CHF：BUY ¥201.84/SELL ¥193.66
TWD：BUY ¥5.48/SELL ¥4.61
MYR：BUY ¥44.70/SELL ¥33.57
VND：BUY ¥0.01/SELL ¥0.004