You download the language pack in the hotel, type a sentence, and watch it come back translated. Box ticked: translation sorted. The test passed — on hotel Wi-Fi, which is the problem. What you proved is that the app works. What you still don't know is whether it works offline.
What a downloaded language pack actually gives you
Google's own wording is careful. Download languages, the help page says, and "this lets you translate them without an internet connection" — typed and pasted text, reliably, with no signal at all.
Camera translation is hedged more than people notice. After downloading a language, Google says, you "could be able to" translate it by looking at it through your camera lens — and the help page then points to a separate list of supported languages. Pointing your phone at a menu or a medicine box offline usually works. Whether it works for your language is a thing to check, not assume.
On iPhone there are two switches rather than one. Apple's Translate app has an On-Device Mode toggle in Settings → Translate, and separately the languages themselves have to be downloaded inside the app. Flipping the toggle without downloading anything gets you a prompt and little else. Apple also warns that on-device results may be less accurate than online ones — true of every on-device model, not a dig at Apple's.
The part that still needs a signal
Live conversation is the hold-the-phone-between-you, back-and-forth mode most people actually picture when they say "I'll just use Translate." Historically it has been the cloud feature, and on most phones it still is.
That changed slightly in September 2026, with conditions worth reading closely. Google began rolling out offline Live Translate, and its support documentation lists it on the Pixel 9, Pixel 10 and Pixel 11. Conversations are limited to English paired with French, German, Portuguese, Italian, Spanish, Hindi, Indonesian, Japanese, Russian or Swedish — and English has to be one side of the pair, so Spanish to Japanese offline isn't on the menu. Older Pixels, phones from other manufacturers and iPhones are all outside it.
Translated into packing-list terms: unless you are holding a recent Pixel and travelling with English on one side, assume live conversation needs a connection until you have proved otherwise on your own handset.
Android's second download, the one nobody mentions
On Android, even offline voice input — dictating instead of typing — is a separate download from the translation language. Offline speech recognition is its own pack, and the menu is named differently depending on who built your phone: Gboard puts it under voice typing, often labelled "Faster voice typing" and offered only on certain models, while Samsung's keyboard has "Install offline language package" under Voice input.
So that is two downloads, in two different settings screens, one of which many people never find. And the offline recogniser is quietly the weaker one: it makes more mistakes on names, technical terms and unfamiliar accents than the cloud version it replaces.
A one-minute test that actually tests it
Do this at home, the week before you fly:
- Download the packs for everywhere you're going — both languages, including your own.
- On iPhone, turn on On-Device Mode as well as downloading the languages.
- On Android, download the offline speech pack separately if your keyboard offers one.
- Turn on airplane mode — and turn Wi-Fi off too. This is the step everybody skips, and it is the entire test.
- Try all four things you'd really use: type a phrase, point the camera at some text, dictate a sentence out loud, and open conversation mode.
Whatever fails in your kitchen is the thing that will fail at a counter with someone waiting. Much better to learn it now.
The bad timing isn't bad luck, it's structural
Offline translation gets tested where there's Wi-Fi: hotel room, café, airport lounge. Sitting down, unhurried, nothing at stake.
It gets needed at a pharmacy counter, a taxi window, a ticket desk, a clinic reception, a roadside checkpoint. Standing up, often outdoors, usually with somebody waiting for your answer — and those are precisely the places with no guest network to join. The moment of maximum need and the moment of minimum connection are the same moment, which is why a feature that quietly requires a signal fails so memorably.
The download itself is the trap closing: a language pack needs the connection you don't have, so you cannot fix any of this from the taxi.
The unglamorous fix
Download the packs anyway. They are your floor — the metro tunnel, the mountain pass, the ferry, the hour after your battery dies and comes back.
But notice that every limit above dissolves the moment the phone has a working connection: conversation mode on any handset, camera translation in any supported language, the larger cloud models that cope better with names and accents, and the phrase your pack doesn't contain. Plus the map to the pharmacy, and whether it's open.
That is what a VamosData eSIM is for — data from the moment you land, installed before you fly, on your own phone, with your home number still live on your existing SIM for calls and bank codes. Check your handset supports eSIM with the device checker, then look at the plans for where you're going on destinations. If you want the wider arrival routine, the first 30 minutes in a new country covers the rest of it, and how much data you actually need covers the sizing.
Belt and braces beats either alone: download the packs and arrive with data. The packs cover the gaps in your signal, and the signal covers the gaps in your packs.