Yes, you can exchange on weekends and holidays.
USD：BUY ¥158.58/SELL ¥154.20
EUR：BUY ¥185.28/SELL ¥180.80
GBP：BUY ¥215.07/SELL ¥202.97
CNY：BUY ¥23.91/SELL ¥21.36
HKD：BUY ¥21.17/SELL ¥18.77
KRW：BUY ¥0.1192/SELL ¥0.0939
PHP：BUY ¥2.98/SELL ¥2.41
SGD：BUY ¥126.17/SELL ¥119.32
THB：BUY ¥5.30/SELL ¥4.50
CAD：BUY ¥118.09/SELL ¥109.81
AUD：BUY ¥116.12/SELL ¥104.86
NZD：BUY ¥98.17/SELL ¥87.98
CHF：BUY ¥201.38/SELL ¥195.16
TWD：BUY ¥5.40/SELL ¥4.55
MYR：BUY ¥44.80/SELL ¥35.55
VND：BUY ¥0.01/SELL ¥0.004