Yes, you can exchange on weekends and holidays.
USD：BUY ¥159.98/SELL ¥155.70
EUR：BUY ¥184.98/SELL ¥180.50
GBP：BUY ¥215.25/SELL ¥202.69
CNY：BUY ¥24.12/SELL ¥21.54
HKD：BUY ¥21.33/SELL ¥18.93
KRW：BUY ¥0.1162/SELL ¥0.0913
PHP：BUY ¥2.92/SELL ¥2.32
SGD：BUY ¥126.16/SELL ¥119.14
THB：BUY ¥5.19/SELL ¥4.38
CAD：BUY ¥117.40/SELL ¥109.00
AUD：BUY ¥114.03/SELL ¥102.62
NZD：BUY ¥95.54/SELL ¥85.11
CHF：BUY ¥199.54/SELL ¥193.47
TWD：BUY ¥5.40/SELL ¥4.55
MYR：BUY ¥44.24/SELL ¥34.93
VND：BUY ¥0.01/SELL ¥0.004