Mobile internet data and call plans in Malaysia are rather affordable, a starter pack can be as cheap as RM15 for 6GB of data.

Mobile Data Plan
According to Open Signal's independent Mobile Network Experience Report (Sep 2022), Digi provides the fastest average Download Speed, best video experience and leads in Excellent Consistent Quality followed by Unifi, then Maxis. Celcom offers the best 4G Coverage followed by Digi and Maxis. Maxis beats the competition on the quality of experience when it comes to playing multiplayer mobile games in Malaysia. U Mobile provides the best Voice App Experience. Yes Network is top for Availability.

Recently Celcom and Digi have merged and together they can bring you the best of both networks. 

Where to Buy and Register Mobile Phone & Data Plan at the Airport:

KLIA
------------------------------
7 Eleven (KLIA Main Terminal Building Departure Hall, Level 5, Lot No. MTB-5-L20 | Shop Hours: 24 Hours)
Digi Store (MTBAP No.5, Public Concourse Arrival Hall | Tel: 6 016 - 299 8888 | Operating Hours: 24 hours)
Maxis Centre (Lot No. 2, Contact Pier, International Arrival, KLIA | Operating Hours: 6:00 am - 12:00 am)

KLIA 2 (Terminal 2)
------------------------------
myNews.com Convenience Store (KLIA2 Gate J (Level 1A), S1-1A-A07A | Shop Hours: 07.00AM - 11:00PM)
7 Eleven, L3-05, Level 3, Gateway@klia2 mall | 24 hours
Maxis Mobile Sdn Bhd, Lot No S2-2-1C03B, Arrival Hall, Public Concourse klia2 | 24 hours
U Mobile (L2-74 on Level 2 of the Gateway@klia2 mall, Arrival Hall | 24 hours)

For tourist, buy the Starter Pack which has a new SIM card or e-SIM registration.

Digi Starter Pack RM10 - 5GB high speed internet

Digi Prepaid NEXT35 (for top up) for Unlimited Social (TikTok, IG, FB, Twitter) + 30GB data for 30 days High Speed Internet at RM35 | RM0.10/SMS. Follow the instructions to activate. You will receive an email from Digi with your activation code within 24 hours after purchase.