Before you start

Passport and valid Indian visa
Proof of a Kolkata address — a hotel or serviced-apartment letter is accepted early on
Passport photographs
An unlocked handset; confirm eSIM support at the store rather than assuming it

Step-by-step

1
Bridge the first days with a travel eSIM
A data-only eSIM bought before departure means you land connected while KYC runs. It gives you no Indian number, so treat it as a bridge rather than a solution.
Mobile appWho: YouDay 0
2
Go to a company-owned Jio, Airtel or Vi store
Branded stores around Park Street, Camac Street, Salt Lake Sector V and the larger malls process foreign passport KYC routinely. Small shops in the older markets frequently cannot.
In personWho: YouWeek 1
3
Bring a full document set
Passport, visa, address proof, photographs, employer letter and FRRO registration where you have it. Requirements vary by operator and store, and a complete set avoids a second trip.
In personWho: You
4
Complete tele-verification promptly
The SIM typically receives calls before it can make them. An automated verification call confirms your details and only then do outgoing calls and data activate — anything from half an hour to two days.
Mobile appWho: You
5
Register the number with your bank and link UPI
The number registered with your bank is the number UPI will use. Get it right the first time; changing it later is a branch process.
Mobile appWho: YouWeek 2
6
Diarise the SIM's validity with your visa
Connections issued to foreign nationals are commonly capped to visa duration and need re-verification when the visa is extended. Losing the number takes UPI and banking one-time passwords with it.
In personWho: You

Documents you’ll need

Original passport and visa page
Proof of Kolkata address
Passport photograph
Employer letter, and FRRO registration where available

Things most newcomers don’t know

Losing the number means losing access to your money, not just your calls.

Indian financial infrastructure runs on the mobile number: UPI is bound to it, bank one-time passwords arrive on it, account alerts go to it. A SIM deactivated because a verification call was missed, or a visa-linked validity lapsed, locks you out of payments entirely. That is the whole argument for an official operator store and same-day verification.

Source: community-reported

Coverage collapses in the Sundarbans and the eastern hills, and those are exactly where you will go.

Kolkata's own coverage is good, but the Sundarbans delta a few hours south has extensive dead zones between islands, and the Darjeeling hills and the north-east are patchy. These are the standard weekend destinations from Kolkata. Download offline maps, tell someone your route, and do not assume a working phone on a boat in the delta.

Source: community-reported

The city loses connectivity during Durga Puja for capacity reasons, not coverage ones.

During Puja, millions of people move through concentrated areas of the city on foot over five days, and mobile networks in the pandal districts congest severely — calls fail and data crawls in precisely the crowds where you are most likely to lose the people you came with. Locals agree meeting points in advance rather than relying on phones. Do the same in your first Puja.

Source: community-reported

Home fibre here is cheap, fast and widely available, including in the old city.

Kolkata has unusually good fixed broadband penetration for its income level, with strong local operators alongside Jio and Airtel, and prices at the low end of the Indian range. Even older north Kolkata buildings are commonly well served. If you work from home, this is one of the easier Indian cities to do it in — but ask which operators reach the specific building rather than the neighbourhood.

Source: community-reported