Yes, you can exchange on weekends and holidays.
USD：BUY ¥159.98/SELL ¥155.85
EUR：BUY ¥185.98/SELL ¥181.50
GBP：BUY ¥218.17/SELL ¥205.65
CNY：BUY ¥24.37/SELL ¥21.80
HKD：BUY ¥21.33/SELL ¥19.01
KRW：BUY ¥0.1163/SELL ¥0.0912
PHP：BUY ¥2.85/SELL ¥1.27
SGD：BUY ¥126.71/SELL ¥117.91
THB：BUY ¥5.21/SELL ¥4.40
CAD：BUY ¥118.00/SELL ¥109.77
AUD：BUY ¥117.74/SELL ¥106.45
NZD：BUY ¥97.92/SELL ¥87.64
CHF：BUY ¥202.02/SELL ¥195.92
TWD：BUY ¥5.48/SELL ¥4.61
MYR：BUY ¥44.79/SELL ¥35.71
VND：BUY ¥0.01/SELL ¥0.004