The Mobile Number Portability Act has been recently signed into law by President Duterte.

The law makes mobile numbers “portable,” ensuring consumers that they may keep their mobile numbers if they ever switch to a different telco provider or change their subscription plans. According to the measure, telco companies should allow their consumers to keep their mobile numbers free of charge. It should also only take companies 48 hours to completely process the switch or subscription change.

Telecommunication firms will be fined a fee of up to 1 million should they fail to follow the law. Their franchise to operate will also be revoked should they still “unjustly refuse even after mediation” by the fifth time.
The National Telecommunications Commission (NTC) was also certified by the law to pay up to PHP 40,000 in damages to each subscriber. The NTC was first urged to order telco companies to adopt Mobile Number Portability in 2017.
Source: ABS-CBN

Smart does not implement it yet as of now