Mobile phone
704% more expensive than in Malaysia
You can buy a SIM card for about 311.79 TWD (41.66 MYR), which includes 1 GB of data plan. You can choose from 4 telecoms: Chunghwa Telecom, FarEasTone, T Star or Taiwan Mobile.
Mobile phones
Taiwan uses similar GSM mobile networks (GSM 900 and GSM 1800) as Malaysia so you should be able to normally use your mobile phone.
Roaming
If you don't want to buy SIM card in Taiwan upon arrival, make sure to check the roaming charges with your telecom provider before your departure so there are no surprises when you return home.