Before you start

The passport you entered on, for SIM registration and for customs IMEI registration
An unlocked handset, and its IMEI number — dial *#06# to display it
Your entry stamp or e-visa, required for customs device registration
For home broadband: proof of address and, for most providers, a KITAS

Step-by-step

1
Buy the SIM at an operator store or a mall counter, not at the airport
Telkomsel GraPARI, Indosat, XLSMART and Tri all have staffed outlets across Jakarta's malls. Airport counters charge a substantial premium for the same package. Bring your passport; the clerk completes the registration on the spot, which is the easiest way to get it done correctly.
In personWho: You15–20 minutes; activation within minutes to an hourA generous monthly data package generally runs a low six-figure rupiah sum in town, roughly double at the airport
2
Register the SIM against your passport
Registration is compulsory and the line will not activate without it. Foreigners register with passport details; there is a cap on how many numbers one identity may hold per operator, so do not let a shop register a spare line in your name that you will never use. Verify the number is registered to you before you leave the counter.
In personWho: You, with the store completing the filingImmediateIncluded in the SIM price
3
Register your handset's IMEI with customs on arrival
A foreign-bought phone works on Indonesian networks for roughly 90 days and is then blocked at device level. Registering at the Bea Cukai customs desk in the arrivals hall is free for devices under a value threshold and is much cheaper than doing it later, when import duty on the full value can be assessed. Do it while you are still in the terminal — it takes half an hour and cannot be done retroactively without cost.
In personWho: You, at airport customsAbout 30 minutes on arrivalFree below the duty-free value threshold; import duty above it or if registered late
4
Sort home broadband through the building, not the market
In an apartment, which fibre providers can reach you is decided by the building, not by you — IndiHome, Biznet, MyRepublic, First Media and others each have buildings they serve and buildings they do not. Ask the management office which providers are already wired in before signing the lease, because retrofitting is slow and sometimes refused. In a landed house you have more choice but installation can take weeks.
In personWho: You, with the building managementDays to weeksRoughly IDR 300,000–700,000 a month for a workable home fibre package
5
Keep a backup network if you work from home
Jakarta fibre is fast and cheap but outages happen, and wet-season power cuts take the router with them. Most people who work remotely keep a second SIM on a different operator with a data package, and tether when the fibre drops. This is cheap insurance rather than paranoia.
Mobile appWho: YouA second data-only SIM is inexpensive

Documents you’ll need

Passport photo page — for SIM registration and customs device registration
Entry stamp or e-visa, for the IMEI registration
Handset IMEI number, from *#06#
KITAS and address proof, for a postpaid line or home broadband contract

Things most newcomers don’t know

The 90-day cut-off is tied to your handset, not your SIM, so buying a new SIM does not fix it.

Indonesia's IMEI regime blocks unregistered foreign devices at the hardware level. People experience it as 'my phone stopped working' around the three-month mark and respond by buying another SIM, which fails for the same reason. The fix is customs registration of the device, and it is free on arrival and potentially expensive afterwards.

Source: Bea Cukai (Indonesian Customs) IMEI registration

Which fibre provider you can have is a property of the building, not a choice you make.

Jakarta apartment towers are wired by whichever providers negotiated access, and management will not always let another in. If working from home matters, ask the management office for the list of live providers and the actual advertised speeds before signing, not after. Tenants routinely discover the building only offers one provider and it is the slow one.

Source: Practitioner reporting; provider coverage maps

Do not let a shop register a spare number in your name to hit a promotion.

A single passport can hold only a limited number of prepaid lines per operator. Shops sometimes register additional numbers against a customer's identity to clear stock or claim a bonus. Those slots are then gone, and a number registered to you that you do not control is a genuine liability — verify what is registered before you leave.

Source: Indonesian SIM registration rules (Komdigi)

Coverage is not the deciding factor in Jakarta the way it is elsewhere in Indonesia.

Outside Java, Telkomsel's reach is a real differentiator and worth paying for. Inside Jakarta all four networks are dense and fast, so choose on package pricing and on which operator your colleagues use for calls. Guides written for Bali or the outer islands push Telkomsel hard, and that reasoning simply does not transfer to the capital.

Source: Operator coverage maps; Indonesian market reporting

Common mistakes to avoid

Assuming a foreign handset will keep working past three months without customs IMEI registration.
Registering the IMEI late and being assessed import duty on the phone's full value instead of registering free on arrival.
Buying a SIM at the airport at roughly double the in-town price when you have Wi-Fi and can wait a day.
Signing an apartment lease before checking which fibre providers the building actually supports.
Letting a shop register extra lines under your passport, using up your per-operator allowance.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.