Yes, you can exchange on weekends and holidays.
USD：BUY ¥162.78/SELL ¥158.40
EUR：BUY ¥185.72/SELL ¥181.02
GBP：BUY ¥219.33/SELL ¥206.83
CNY：BUY ¥24.78/SELL ¥22.17
HKD：BUY ¥21.67/SELL ¥19.26
KRW：BUY ¥0.1174/SELL ¥0.0921
PHP：BUY ¥2.90/SELL ¥2.31
SGD：BUY ¥127.14/SELL ¥120.11
THB：BUY ¥5.19/SELL ¥4.38
CAD：BUY ¥116.80/SELL ¥108.09
AUD：BUY ¥116.02/SELL ¥104.63
NZD：BUY ¥96.75/SELL ¥86.20
CHF：BUY ¥200.47/SELL ¥194.26
TWD：BUY ¥5.47/SELL ¥4.61
MYR：BUY ¥44.20/SELL ¥35.14
VND：BUY ¥0.01/SELL ¥0.004