Yes, you can exchange on weekends and holidays.
USD：BUY ¥160.28/SELL ¥156.00
EUR：BUY ¥187.78/SELL ¥183.20
GBP：BUY ¥218.44/SELL ¥205.92
CNY：BUY ¥24.37/SELL ¥21.75
HKD：BUY ¥21.42/SELL ¥19.03
KRW：BUY ¥0.1190/SELL ¥0.0941
PHP：BUY ¥2.94/SELL ¥2.35
SGD：BUY ¥127.31/SELL ¥120.22
THB：BUY ¥5.27/SELL ¥4.46
CAD：BUY ¥118.00/SELL ¥109.66
AUD：BUY ¥116.55/SELL ¥105.16
NZD：BUY ¥97.52/SELL ¥87.09
CHF：BUY ¥201.20/SELL ¥194.93
TWD：BUY ¥5.45/SELL ¥4.61
MYR：BUY ¥44.80/SELL ¥35.56
VND：BUY ¥0.01/SELL ¥0.004