when would cellular option come to UAE

Hi

Apple advises that Apple Watch Series 3 (GPS + Cellular) will become available in other countries next year, but it has not yet specified when and where.

I suggest that you monitor the Apple Online Store in the UAE for further information regarding availability in due course:

Apple Watch Series 3 - Apple

I'm afraid that, in the meantime, no-one here can tell you anything about Apple's unannounced plans. You are not talking to Apple here - this is a user-based technical support community.