2 years.
The penalty to pay is the pro-rated amount you paid for your Lucky number.
For example, my lucky number costs $28. I stayed for a month plus another 4 days before I initiated the port out after signing up ZYM.
So, I was charged $27.76 for the penalty.
For porting out. You must pay the penalty over the counter first so that SIMBA can release its number for porting.
Very Important!!!!!!!!
You must tell simba staff that you are porting out, and not terminating the lucky number.
So, you should purchase a new telco plan with port in option and then quicky go to simba service counter (Ubi HQ) to pay the penalty so that simba can release its number for porting immediately.
My case was that I forgot about paying the penalty. Thus my port out to ZYM failed. So, yesterday at about 330pm. I paid the penalty over the counter and WhatsApp ZYM customer service to reinstate my porting, and the porting process stated last night at 11pm, and by 1230am, my simba lucky number was ported into ZYM.