Yes, you can exchange on weekends and holidays.
USD：BUY ¥158.48/SELL ¥153.80
EUR：BUY ¥179.58/SELL ¥174.62
GBP：BUY ¥213.19/SELL ¥199.55
CNY：BUY ¥24.51/SELL ¥21.85
HKD：BUY ¥21.16/SELL ¥18.78
KRW：BUY ¥0.1274/SELL ¥0.1022
PHP：BUY ¥2.78/SELL ¥2.20
SGD：BUY ¥125.66/SELL ¥118.55
THB：BUY ¥5.06/SELL ¥4.25
CAD：BUY ¥113.68/SELL ¥104.84
AUD：BUY ¥113.4/SELL ¥102.60
NZD：BUY ¥92.91/SELL ¥82.00
CHF：BUY ¥190.33/SELL ¥183.56
TWD：BUY ¥5.37/SELL ¥4.51
MYR：BUY ¥43.25/SELL ¥34.14
VND：BUY ¥0.01/SELL ¥0.004