'I'm in Japan, but ChatGPT won't open' — yes, this really happens
You're travelling in Japan, your eSIM shows full signal, and yet ChatGPT is the one thing that won't load — or your Instagram post keeps failing to upload. It's a complaint that comes up again and again on social media and travel forums.
The cause isn't your signal, and it isn't your phone — it's which country that eSIM routes your traffic through. Travel eSIMs are sold all over the world, and some of the cheapest ones carry your traffic to Japan by way of a mainland China or other third-country network. Your phone may be sitting in Japan, but as far as the internet is concerned, you're 'connecting from China' or 'connecting from Hong Kong'.
Why it fails — what the routing point changes
| eSIM routing point (IP country) | ChatGPT | Instagram/TikTok | Japan-facing services | What happens |
|---|---|---|---|---|
| Routes through mainland China | ❌ Blocked | ❌ Blocked | △ | China's access restrictions apply just as they do inside China |
| Third country such as Hong Kong or Singapore | ○ Usually works | ○ | △ Region checks misfire | Rejected by streaming/booking sites; higher latency |
| Japan IP (local connection) | ✅ | ✅ | ✅ | Same conditions as being inside Japan |
There are two distinct levels to keep in mind.
- Mainland China routing = flat-out blocked. ChatGPT, Google and most major social apps other than LINE simply won't work. This is the classic story behind 'I bought a cheap eSIM and every social app died'.
- Third-country routing = subtly off. ChatGPT may run fine, but Japan-facing video streaming, ticket booking and some bank or payment sites can turn you away as 'overseas access'. This is actually the more common way to get tripped up while travelling.
Before-you-buy checklist for spotting one
Check the following on the purchase page.
- Does it state 'Japan IP', 'Japanese local line' or 'local breakout'? — If it's spelled out, it's a Japan IP
- Can you confirm it 'does not route through a Chinese carrier'? — Be wary if there's no mention and the price is unusually cheap
- Do the reviews mention 'ChatGPT doesn't work' or 'my social apps got blocked'?
- Still unsure? Ask the seller one question: 'Which country will this eSIM's IP address be in?' — A seller who can't answer on the spot is best avoided
Confirming it after activation is just as simple: open an IP-check site in your browser (search 'what is my ip'), and if the country shown is 'Japan', you're good. If anything other than Japan appears, that eSIM is routing through a third country.
〔Screenshot needed: one photo from a real device showing 'Japan' on an IP-check site. This is the single strongest piece of evidence in the article, so insert it here〕
And a Japan IP does more than just unlock ChatGPT. Your maps and search results come back localized to Japan, you sail through ticket-booking and streaming services that reject foreign IPs, and you no longer need a separate VPN subscription just to stay secure.
Where yah.mobile fits in (an honest rundown)
yah.mobile's eSIM connects directly to a domestic Japanese line on IIJ (an MVNO that leases capacity on the NTT docomo network), so its IP address is in Japan. ChatGPT, Instagram and TikTok work under the same conditions as a phone that lives in Japan (as of July 2026).
That said, let's be straight with you: a Japan IP is not some proprietary yah.mobile technology. Any eSIM that connects directly to a Japanese line gives you exactly the same thing. What matters isn't the brand — it's choosing only after you've checked 'where does it route' — and handing you the means to run that check is the whole point of this article. For current plans and pricing, see the plan table below (identical to the site's main price source, with the confirmation date attached).
〔Editor to confirm/edit: whether we may state the carrier name 'IIJ (MVNO on the docomo network)' in the body text (i.e. whether this external disclosure is permitted)〕
For the full picture on how to choose, see the Complete Japan eSIM Guide, and for a price comparison against other providers, see the Japan eSIM Comparison Table.
