Do i Need Cash when visiting?

I will be visiting Okinawa between the 26-30 June and one day trip to Zamami, do i need Cash for taxies? and do people accept foreign cards (Mastercard/Visa) on Zamami? I saw you could book through DiDi which i used while in china but it might be different system in Japan?
And how is the weather in Okinawa in end of June i'm scared of Typhoons :c

by ScroogeMc_Duck