It becomes mandatory for a legal person in the UAE to register for VAT if the value of taxable imports and supplies in the previous 12 months exceed AED 375,000 per annum.
It is voluntary to register for VAT if your taxable turnover is more than AED 187,500 but less than AED 375,000 per annum.
If in the next 30 days you expect your taxable turnover to cross AED 375,000 per annum you are under an obligation to get yourself registered under VAT.