India

Basics
India has the fastest growing telecom network in the world with about 900 million subscribers. It's also one of the most chaotic to foreigners. These GSM operators share the market: Only 10% of the users are on the two state-owned networks (BSNL, MTNL), the remaining 90% on privately-owned carriers.
 * Bharti Airtel
 * Vodafone India
 * Idea Cellular
 * Reliance Communications (RCom)
 * Reliance JIO (4G/LTE-only)
 * BSNL
 * Aircel (to be merged with RCom)
 * Tata DoCoMo
 * MTNL

Frequencies
This is very straight and one of the few uniformed platforms: 2G/GSM is on 900 and 1800 MHz, all 3G on 2100 MHz up to HSPA+ speed. 4G/LTE is on rare 2300 MHz (TDD-LTE, band 40) and usual 850 and 1800 MHz (FDD-LTE) and will be eventually on 700 MHz too. Besides GSM networks, WIMAX and CDMA is used too, but not part of this survey. CDMA is progressively shut down and the spectrum is refarmed to LTE. So it usually makes no sense to activate CDMA subscriptions.

Coverage:
In 2010 the licences for 3G were auctioned. The result has been a very fragmented situation. Most networks acquired only licences for specific states locally called circles. List of network and circles. 3G network map of India. Airtel, Vodafone and Idea agreed on sharing through a national roaming agreement, but this is often not available for data. So going to India, first check, which network is operating in your destination region: 3G network coverage in India, 4G networks in India. Travelling through India, the widest 3G coverage have Airtel and BSNL (but not in Kolkatta and Dehli).

You can never really rely on one network only as blackouts and congestions are frequent. At other times and places, you may also get worldclass speed and coverage.

Legal requirements:
It is theoretically easy to get a prepaid SIM card in India as a foreigner, you just have to make sure you have all the proper documents and they'll probably want photocopies of them too. These documents you'll probably need: You will need to present these, along with your original passport document, to the SIM vendor. The Indian Government has recently put in restrictions that puts a 3 month limit on prepaid SIM connectivity for foreign visitors to India. Cellphone vendors cannot sell SIM cards with longer than 3 months validity.
 * make a copy of the photo / name page of your passport ,
 * a copy of the Indian visa page in your passport (or your OCI card),
 * and a  passport sized picture  as well.
 * Get a proof of where you're staying in India . If you're in a hotel, you should be able to get a letter from the frontdesk verifying that you are indeed staying there.
 * If your passport doesn't have a home address, try to show something which looks official with it.

As of November 2012, there has been a significant tightening of regulations around the purchase and activation of SIM cards. Some operators are saying that it will take at least 4 days to activate a SIM card once purchased. Officially, this process takes 24-48 hours. In practice, some SIMs are activated within 12 hours since the rule has changed, and other SIMs have taken almost a week to activate. And, just to make things more difficult, there is very little rhyme, reason or logic to how long any of these things take.

In 2015 the process seems mostly to be a bit swifter. Many people report that their SIM cards were activated within 2 days. For latest reports and updates check this forum. But you still have to be prepared that it takes a while and you may be called to confirm your identity or local address. Other users had less luck and again it's unclear why:

"After 3 weeks of trying to get three different SIMs activated, from Airtel, BSNL and Vodafone, we gave up. They had passport scans, driving licence scans, 6 photos, and scans of my local UK utility bills, but they never were activated. We finally had an Indian relative who bought us a card in Hyderabad, using his own Indian ID. It still took a week for it to become activated and then once it was activated, the first phone call goes through les for Jammu and Kashmir state

A prepaid SIM card registered somewhere in India, can be used all over the Union, except in Jammu and Kashmir (State of North India) this is because of the fear of terrorism. Only a new SIM, bought in J&K works in this state. There the restrictions are even higher: you will need 4 passport photos, copies of your passport and your local sponsor (hotel manager or local counterpart) and expect that activation takes even longer. J&K SIM cards have reduced functionality: You can't receive or send text messages.

Airtel (Bharti Airtel)
Airtel (a.k.a. as Bharti Airtel) is the biggest provider in India. It has about 200 million customers and the widest coverage. It has 3G licences in 13 circles and a roaming agreement for voice with Vodafone and Idea. Users recommend them especially for the metropolitan areas. 4G/LTE has started in 296 cities and around 12 circles. It's open for prepaid in some of them: Airtel's 4G cities. Note, that Airtel uses mostly 2300 MHz (on band 40, in TDD-LTE) instead of 1800 MHz (band 3) for LTE.

Availability
Airtel SIM Card Cost : Rs. 50-100, some vendors may charge more. Lifetime validity requires a recharge of Rs. 49

Activation takes 2 hours up to some days. 3G activation takes up another 4 hours after intial SIM card activation. When you buy the card, initially you will have No Network; after some hours, you'll notice network availability; call 59059 to activate. You'll need to give the last four digits of your ID.

Data feature packs
Default data rate depends on prepaid tariff line and region and is mostly around 4p per 10 KB.

Airtel always offers promotions for new customers and their first time recharge. So ask for it. Afterwards 3G/4G data "normal" recharge price applies and they differ between circles. There are no manual activations as such, once the credit is added the data package is activated automatically, with a SMS notification. So every top-urrespondents with a certain allowance. Be sure to top-up the right amount exactly to get the right bundle.

As the top-up face prices and packages sizes differ for every circle, it's not useful to give prices here as they will be changed to a totally different package in a different circle: 4G/LTE is available for prepaid in about 100 towns so far in 2016 like Mumbai, Kolkata, Delhi and many others.
 * for 2G packages (less useful): select "prepaid" and circle and check here
 * for 3G packages: select circle and check here
 * for 4G/LTE packages: select city and check here (scroll down to red boxes)

To apply a feature data pack, you can ask at any shop showing the Airtel logo, which are very widespread. Contrary to most countries, don't just buy the airtime - you need to buy and apply data packs separately.

There are lots of special offers, and data packs can be shared with up to five 'family' members. It's worth downloading the My Airtel app to see all offers and easily apply them; this is only available on the Indian App and Play stores, but expert Android users can Google "my airtel apk" and install it in the usual way.

Domestic roaming has to be switched on to use internet outside the state you purchased the SIM from. But there are no extra charges for this domestic data roaming, but for phone calls there are roaming charges.

Credit balance check: *123#, remaining data check: *123*11# . Click here for many other useful codes.

3G/4G Combo plans: Infinity
In 2015 Airtel launched its prepaid combo plans called Infinity that are valid in all circles where Airtel operates and are on 3G and 4G, valid for 28 days. All packages include unlimited Airtel calls, unlimited local calls, unlimited Wynk music and movies and 100 SMS per day plus: The 7 and 10 GB bundles also include unlimited STD calls and pan-Indian roaming. Overuse fee for all packages is 25p per MB.
 * 1098 Rs.: 3 GB 3G/4G data
 * 1749 Rs.: 5 GB 3G/4G data
 * 2249 Rs: 7 GB 3G/4G data
 * 3249 Rs: 10 GB 3G/4G data

These Infinity plans may be the most expensive in India right now. But they are the most convenient for travellers through different circles as well. Please remember, that for 4G/LTE you'll need a device capable of 2300 MHz TDD-LTE (Band 40) that is still unusual in the rest of the wolrd.

More info

 * APN: airtelgprs.com


 * Airtel number will be released if not logged into the network for 30 days
 * Website in English: http://www.airtel.in/

Vodafone India
Vodafone has the 2nd most subscribers in India and one of the better networks for metropolitan coverage. Some locals consider its 3G as fastest and most reliable in India. It has 3G licences in 9 circles and roaming agreements with Airtel and Idea. In 2015 4G/LTE on 1800 MHz (Band 3) has started in Kochi and has spread to Mumbai, Delhi, Bengaluru and Kolkata and more places in 2016.

Availability
SIM card costs: Rs. 50-100, various vendors may charge whatever they feel like. Recharges are made in their shops or online from Rs. 111 for a credit of Rs. 105 to Rs. 1000.

Data feature packs
Default rate outside of packs is on most prepaid tariffs and circles is around 4p per 10 KB. For prepaid they 4G/LTE, 2G and 3G is widespread available. Like Airtel, their rates and package sizes differ very much from circle to circle. So it doesn't make sense to quote prices here. Hard-capped packages will charge the default rate for overuse, soft-capped packs are called "unlimited" and will throttle down to 56 kbps.
 * 2G, 3G and 4G/LTE packages: select and circle here on top right

Vodafone Flex
In autumn 2016 they've introduced the Flex recharge plans valid in all circles. The offer is available with no pre-fixed quotas for voice, data or SMS. Vodafone Flex customers can carry forward their unused credit.

1 Flex is a unit: every MB data, SMS sent and minute of call incoming costs 1 Flex, every local and roaming call outgoing per min 2 Flex. These Flex packages are sold, each valid for 28 days (prices can vary slightly between circles because of different taxes):
 * 325 Flex: Rs. 119
 * 700 Flex: Rs. 199
 * 1200 Flex: Rs. 299
 * 1750 Flex: Rs. 399

Vodafone U
Aimed at the youth, but publicly available, Vodafone sells these combo plans in all circles vaild for 28 days: Prices differ slightly between circles because of taxes. Every U pack or reload contains Rs.20 calltime, call to one favourite Vodafone number at Rs.0.20 per min and music downloads worth of Rs. 99 through Saavn Pro.
 * Starter packs:
 * U Small: 150 MB + 150 MB night (@ midnight-6am) 3G data: Rs. 85-90
 * U Large: 1 GB + 500 MB night (@ midnight-6am) 3G data: Rs. 180-190
 * Reloads:
 * U Small: see above: Rs. 99-106
 * U Medium: 300 MB + 300 MB night (@ midnight - 6am): Rs. 169-179
 * U Large: see above: Rs. 280-301

More info

 * APN: www
 * Website: http://www.vodafone.in

Idea Cellular
Idea is the 3rd provider in India with a market share of around 15%. It has 3G licences in 11 circles and offers service in 14 circles through network sharing with Vodafone and Aircel. For a survey, check their website or here. In 2015 it started with 4G/LTE and in 2016 it already covers 150 cities in about 10 circles (list) on 1800 MHz (Band 3).

Availability
SIM card costs: Rs.10 + 1.10 tax, various vendors may charge whatever they feel like. Default data rate is around 3p per 10 KB.

2G and 3G packages
Idea has very competitive prices for packages, slightly below the level of Airtel or Vodafone. However, their prices differ widely according to state/circle. Generally they sell 3 kinds of data packs: For the exact packages and prices of 2G and 3G packages, you need to check their website here and first select circle on the right.
 * Sachet packs: for small data amounts, often charged by the minute and for 20 mins only at around 7 Rs.
 * Limited volume packs: for medium data amounts, 300 MB to 3 GB per month, hard-capped, overuse around 4p per 10 KB.
 * "unlimited" volume packs: for big data, 3 GB to 15 GB, soft-capped, throttled to 40 or 20 kbps when reached quota
 * special packs, like night traffic, add-ons, WhatsApp packs, only offered in some markets

4G/LTE packages
At the beginning of 2016 LTE was available on prepaid in these circles: Andrha Pradesh, Karnataka, Kerala, Madhya Pradesh & Chattisgarh, Punjab and Tamil Nadu & Cennai.

For prices and packages check their website here and first select circle.

More info

 * APN: internet
 * Website: http://www.ideacellular.com

Reliance Communications (RCom)
Reliance Communications (RCom) is the 4th provider in India holding licences in all 22 circles on 2G or 3G. It runs a CDMA network too (imcompatible to GSM) about to be shut down. It's 4G is through sharing with JIO (see below).

In September 2016 it was announced that it has acquired Aircel (see below) to be merged to their network soon.

Availability
SIM card costs: Rs. 50-100, various vendors may charge whatever they feel like.

Data feature packages
Their pay as you go rate is a pretty high 10 Rs. per 10 KB.

They offer this anchor pack for all circles: for Rs. 177, you get 1GB 3G data and unlimited Facebook, Whatsapp and Twitter in all regions in 30 days. To activate type *777*177#. Overuse is 3p per 10 KB.

For some states, they have special plans, packages and offers you can check here

Data-only SIM
They offer data-only SIMs too which has no voice and is intended for tablets or modems. These packages are offered for the data card in all circles: In all circles special packages and pricings are offered and can be checked here.
 * 7.2 Mbps USB Data Card: Rs. 1,499
 * 21.6 Mbps USB Data Card: Rs. 1,999

More info

 * APN: rcomnet / OR/ smartnet
 * Website: http://www.rcom.co.in

Jio
Reliance Jio Infocomm (RJIL), the mobile arm of petrochemical giant Reliance Industries Ltd. (RIL) owned by India's richest man Mukesh Ambani, started its new 4G-only network in 2015/6 in all circles.

In August 2016 RJIL started a price war on their new 4G/LTE network. The operator currently covers 18,000 cities and 200,000 villages in 22 circles and plans to cover 90% of the population by March 2017 with 4G/LTE. On their new JIO offer, there is no fallback to 2G or 3G. You'll need to have a device capable of LTE on 2300 MHz in TDD-LTE (band 40).

Under it's welcome offer, all Jio services including voice, apps, and 4G/LTE data will be available free of cost from Sep 5 to Dec 31, 2016. Long lines have been building up in front of their stores already.

Eventually, the will be monthly data plans. All voice calls for Jio customers made through 4G/LTE (VoLTE) are absolutely free, roaming charges are also be zero between circles. Base rate is 1/10 of the other providers at Rs.50 per GB. These plans have been introduced in all circles valid for 28 days: Packages from 4 GB include unlimited night traffic, unlimited SMS, unlimited voice to all Indian networks (through VoLTE - on suitable devices only), and the double data amount additionally through India's largest WiFi network called JIONet. As their SIM cards are in high demand, expect delays and problems like overcrowding of their network. For an unexperienced visitor, it can't be recommended so far as Jio faces a blockade of the other carriers. In September 2016 about 80% of all calls to other networks failed.
 * 300 MB: Rs.149
 * 4 GB: Rs. 499
 * 10 GB: Rs. 999
 * 20 GB: Rs. 1499
 * 35 GB: Rs. 2499
 * 60 GB: Rs. 3999
 * 75 GB: Rs. 4999

More info

 * APN: jionet
 * Website: http://www.jio.com

BSNL
BSNL for Bharat Sanchar Nigam Limited is an Indian state-owned telecommunications company. It operates in all circles except the cities of Mumbai and New Dehli where MTNL operates instead (see below). This provider is seen as not so reliable in the cities, but is in some provinces the only 3G option. So better make a network scan before you buy a SIM card. BSNL has spectrum for 4G on 2500 MHz TDD-LTE (Band 41), that is not marketed for prepaid up to now.

Availability
They sell a prepaid data SIM with voice for Rs. 20 with a 96 Rs. voucher as a normal SIM or for Rs. 59 as USIM. This includes 500 MB vaild for 30 days. These packages below can be booked for 2G and 3G.

Data feature packages
* = promotion. Other plans and offers may apply regionally and can be found on their website

More info

 * APN: bsnlnet
 * Website: http://bsnl.in

Aircel
Aircel is the 6th largest mobile provider in India with a market share of about 8%. It's mostly owned by Malaysian Maxis. It has 3G licences for 13 circles and started 4G/LTE as TDD-LTE on 2300 MHz (Band 40) in 2014, that is not available for prepaid yet.

In September 2016, RCom and Maxis Communications announced that they would merge their mobile network operators. The brand Aircel will eventually be dropped and integrated into RCom (see above).

Availability
Their start-up kit is available where they have a 3G coverage. So you don't find it in Mumbai or Dehli, but in Kolkata. Check aircel coverage map first. It's sold for 28 Rs. including taxes. Top-ups are available Rs. 10-1500. For online recharges, Airtel offers 20% data bonus.

Data feature packages
Data by default is 15p per MB. Internet packages are called Pocket Internet. These packs are sold in Delhi: For other circles and places, check their website and adjust circle on top first.

More info

 * APN: aircelgprs
 * Website: http://www.aircel.com

TaTa DoCoMo (Virgin mobile India, Tata Indicom)
DoCoMo has only acquired licenses in 9 circles. So it has quite a limited network coverage in India for 3G see here, but at good prices if you need it there. Download list of 3G towns,

Availability
Starter pack is sold for 35 - 49 Rs. in their stores.

Data feature packages
DoCoMo, Virgin Mobile and Tata Indicom in Dehli have very low prices. They differ immensely on the circle you are in. Note that the nationwide coverage in India is very limited however. For exact prices in your circle, check their websites (see below).

More info

 * APN for DoCoMo: tata.docomo.internet
 * APN for Virgin Mobile: vinternet.in
 * Website of DoCoMo: http://www.tatadocomo.com/
 * Website of Virgin Mobile: http://www.virginmobile.in
 * Website cof Tata Indicom (in Dehli): http://www.tataindicom.com/

MTNL
MTNL for Mahanagar Telephone Nigam Ltd. is a state-owned telecommunications service provider in the metro cities of Mumbai and New Delhi. They operate only there and in two different branches for Mumbai and Delhi.

MTNL in Mumbai
MTNL sells a broad and quite cheap variety of data packs for Mumbai: check data-packs

MTNL in New Dehli
Likewise, MTNL sells similar very cheap packs in Delhi, check here and tick data plans

More info

 * APN for Mumbai and Delhi: mtnl.net
 * Website MTNL Mumbai: http://mtnlmumbai.in
 * Website MTNL New Delhi: http://mtnldelhi.in