Staying connected: eSIMs, the apps that run Thailand, and the Indian number.

The eSIM, before departure

Thailand's mobile networks are fast and coverage in the places wealthy visitors actually go is effectively total. The efficient move is a Thai or regional data eSIM bought online and installed at home: the QR code arrives by email, installation takes two minutes, and the line activates on landing, which means maps, WhatsApp and the driver's messages work at the aircraft door. Tourist eSIM packages with generous data cost a few hundred baht for a typical stay. For longer stays and households, a proper Thai number on one of the main networks is worth having, arranged with passport registration; we set these up for clients so nobody spends an afternoon at a telecom counter. The one technical check before travel: confirm the handset is eSIM-capable and carrier-unlocked, because discovering otherwise at Suvarnabhumi converts a two-minute task into an errand.

Keeping the Indian number alive

The Indian SIM must not die abroad, because Indian banking, UPI, Aadhaar-linked services and half of daily life authenticate by SMS OTP to that number. The pattern that works: the Indian SIM stays in the phone's second slot with international roaming enabled but mobile data switched off for that line, so it receives SMS at trivial cost while the Thai eSIM carries all data. Before departure, confirm with the Indian operator that roaming is active and, for long stays, that the plan will not lapse for non-recharge; a small recharge calendar reminder every validity period keeps the number safe. Families staying months should also register alternate authentication where their banks allow it. Losing the OTP number mid-stay is the single most disruptive small failure we see, and it is entirely preventable.

The apps that run Thailand

• Grab: cars, food delivery and couriers; the working answer whenever the driver is off duty. Attach an international card before travelling.
• LINE: Thailand's default messenger for everything local, from condo management to restaurant bookings; install it and let contacts accumulate.
• WhatsApp: works exactly as in India and remains the family's own channel; nothing to change.
• Google Maps: excellent in Thailand, including transit and traffic; save the house, the office and the school as favourites on day one.
• Food delivery beyond Grab: the local platforms widen the range in Bangkok; the household staff will have opinions.
• Banking apps, Indian and Thai: confirm each opens abroad before departure; a handful of Indian apps object to foreign networks until settings are adjusted.
• A translation app with Thai downloaded offline: needed rarely, invaluable when needed.

Wi-Fi, hotels and houses

Hotel and villa Wi-Fi at the level our clients stay is dependable, and Bangkok's fibre packages for residences are fast and inexpensive by any standard; for a household staying a season we have fibre installed in the first week. Two habits worth keeping from the family office playbook: video calls to India sit best on Wi-Fi rather than mobile data for stability, and anything financially sensitive belongs on the home or hotel network or the phone's own data, never on cafe Wi-Fi. VPNs work normally in Thailand; corporate users will notice nothing unusual.

Calls to and from India

In practice, voice has moved almost entirely to WhatsApp and FaceTime on both sides of this corridor, and the quality on Thai networks is excellent. The Indian number's roaming voice rates are best treated as an emergency channel rather than a habit. For the family's Thai life, the Thai number handles restaurants, drivers and deliveries; for everything Indian, the apps carry it. Elderly parents travelling with the family sometimes prefer a simple arrangement: their own phone untouched, on roaming for calls and SMS, with the household's Wi-Fi carrying their WhatsApp video calls to home. Simplicity there is worth more than efficiency.

Households, staff and the second phone

A household is a small network, and it works best designed as one. The driver, the housekeeper and the coordinator sit in one group with the family's designated organiser, which in practice means one adult who does not mind being the switchboard. Staff travelling with the family from India need the same treatment as everyone else, a Thai line and their Indian number kept alive, because the cook who cannot receive an OTP cannot pay her own bills at home, and that becomes the household's problem soon enough. For principals who run separate work and personal phones, the pattern is to put the Thai eSIM on the phone that travels everywhere and leave the second phone on Wi-Fi and roaming; two full plans is money spent on tidiness. Children's phones get the data eSIM and nothing else to think about.

When the OTP fails anyway

Even a well built setup meets the occasional failure: an Indian bank that sends the SMS late, a roaming hiccup, a handset that dropped the second line without mentioning it. The playbook is short. Restart the phone first, because a re-registration on the roaming network cures most silences. Check that the Indian line shows connected to a Thai network at all, and toggle it if not. Move the transaction to an app-based approval where the bank offers one, which is why those approvals are worth enabling before travel. And if the number has genuinely gone dark, the Indian operator's app can usually revive roaming or recharge from abroad, which is the moment the plan to keep that app installed and logged in pays for itself. What the playbook never includes is disabling the Indian SIM in frustration; a dead second slot is recoverable, a deleted line from Bangkok is a genuine errand.

SIM registration rules, roaming tariffs and app availability change; Thai SIM registration requires a passport and the details are set by the operators and regulator. Verify current terms with the mobile operators and your Indian carrier before travel; this reflects mid-2026 practice.

The office standard

We treat connectivity as part of the arrival, not an errand after it: eSIMs installed and tested before wheels-up, the Indian line's roaming confirmed, the app list checked against each family member's phone, and a Thai household number established for longer stays. The measure of success is the same as everywhere else in the first week: the family never thinks about it again. Of everything in the settling-in series, this is the piece most completely solvable from an armchair in India, which is why it is the one we insist is finished before anyone drives to the airport.

This briefing is general information, not legal, tax or investment advice. Thai rules change frequently and individual cases differ. Verify current requirements with the relevant authorities, including the Immigration Bureau, the Board of Investment, the Land Department, the Department of Business Development and the Revenue Department, and take advice on your own facts before acting.