Yes, you can exchange on weekends and holidays.
USD：BUY ¥159.98/SELL ¥156.00
EUR：BUY ¥186.18/SELL ¥181.65
GBP：BUY ¥216.90/SELL ¥204.24
CNY：BUY ¥24.31/SELL ¥21.68
HKD：BUY ¥21.39/SELL ¥19.00
KRW：BUY ¥0.1187/SELL ¥0.0939
PHP：BUY ¥2.95/SELL ¥2.36
SGD：BUY ¥126.79/SELL ¥119.78
THB：BUY ¥5.25/SELL ¥4.43
CAD：BUY ¥117.60/SELL ¥109.14
AUD：BUY ¥115.77/SELL ¥104.40
NZD：BUY ¥97.05/SELL ¥86.59
CHF：BUY ¥200.31/SELL ¥193.97
TWD：BUY ¥5.42/SELL ¥4.57
MYR：BUY ¥44.54/SELL ¥35.28
VND：BUY ¥0.01/SELL ¥0.004