How do phone and data plans work in Indonesia?

Mobile data in Indonesia is inexpensive and generally good in the developed areas, and the administration around it catches people.

Registration

SIM cards must be registered to an identity document. For a foreigner that means your passport, and increasingly the registration is done at the point of purchase with the vendor.

Buy from an official provider store or a reputable outlet, not a stall at the airport charging several times the price for a card that may be registered to someone else. A SIM registered to a stranger is a SIM you can lose access to.

Keep the number and the registration details. Porting, recovering a number and dealing with a provider all require them.

Coverage

Good across the developed south — Denpasar, Kuta, Seminyak, Canggu, Sanur, Nusa Dua, Ubud — with 4G everywhere and 5G in parts.

Thinner as you move out. The interior Bukit, the highlands, the east, the north and the islands all vary, and coverage can be patchy even where a map says otherwise.

In a tourist area at peak, the local cell gets busy, and speeds degrade precisely when the most people are using them. That matters if you are relying on mobile data as a primary connection.

Cost

Inexpensive by international standards. Data packages are cheap, generous and widely available, topped up through apps, convenience stores and provider outlets.

For most people the practical decision is simply which provider has the best coverage where they actually spend time, which is a local question rather than a national one. Ask people in the specific area.

eSIM and roaming

eSIM is available from Indonesian providers and from international travel-eSIM services, which is convenient for short stays and removes the registration friction.

Roaming on a home plan is expensive for anything beyond a few days and is generally the wrong answer for a stay of any length.

For a visit of a week or more, a local SIM or eSIM is straightforwardly better.

For a villa owner

Two points that matter commercially.

A mobile backup connection for the property costs little and saves a bad review when the fibre goes down, which it does — more often in the wet season. A mobile router as a fallback is the cheapest insurance available on a property marketing itself to remote workers.

Do not rely on mobile as a primary connection in a villa in a tourist area. It degrades at peak, which is when your guests are there. Fibre where it reaches is the answer, and availability is address-specific rather than area-specific.

Keeping a number after you leave

This is the part that catches people.

Indonesian numbers deactivate if left unused or untopped for a period, and once a number is released it can be reassigned.

That matters more than it sounds, because your Indonesian number is frequently tied to:

Banking, including two-factor authentication on an account holding rental income.

Government and tax portals.

Utility and service accounts.

Ride-hailing and payment apps holding a balance.

An owner who leaves, lets the number lapse, and then cannot receive the code needed to access their Indonesian bank account has a genuinely annoying problem to solve from abroad.

Keep the number alive with a minimal top-up if you retain any Indonesian accounts, or deliberately move the authentication before you go. Handle it as part of leaving rather than discovering it afterwards.

Practical advice

Buy from an official outlet with your passport, and keep the registration details.

Ask locally which provider works where you will be, rather than assuming.

Get fibre at the property if it reaches, and keep mobile as backup.

Keep the number alive if you hold Indonesian accounts.

Use an eSIM for short visits.