The short answer
On O2 Travel your UK phone works in Japan for £7 a day (about $9), charged only for the days it is used. Ringo Light covers the trip once instead: 3 days at $9.99, 2 weeks at $21.99, 30 days at $54.99, with unlimited data at full speed. O2 offers what a mobile plan does best, your own number, calls and texts and no eSIM slot, and I give it that.
The Japan trip is paid once, $9.99 for three days, $21.99 for two weeks or $54.99 for thirty, at full speed on a Shinkansen or a hotspot. O2 Travel bills £7 each day of use and holds data to 2Mbps.
Your UK number rings in Tokyo as it does in Leeds, texts come through, and the day charge sits on your usual O2 bill. No app, no QR code, and handsets without eSIM still work. Ringo Light does data and nothing else.
Prices read on 31 October 2026: O2, Ringo Light, European Central Bank on their own sites or listings, Ringo Light from its catalogue. All in US dollars unless stated. Treat every number as a snapshot.
See the full price index for every country.
Travelling further? Compare the best eSIM for Asia and the eSIM for Asia-Pacific.
The prices, charted
US dollars, 31 October 2026. O2 bills days of use only, so fourteen charges is the most it can reach in a Japanese fortnight. Pounds change into dollars at the ECB reference rate from 30 October 2026, newest on 31 October, £1 = $1.34.
O2's page shows no monthly bolt-on, so thirty days in Japan is thirty daily charges. Converted at the ECB rate of 30 October 2026, £1 = $1.34. Ringo Light covers the month in a single payment.
Three days in Tokyo at each, at the ECB reference rate of 30 October 2026, £1 = $1.34. O2 alone also brings your calls and texts.
Side by side
Swipe to compare →
Head to head
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- Nomad vs Ubigi for Japan
- Holafly vs Nomad for Japan
- Airalo vs Ringo Light for Japan
- Airalo vs Holafly for Japan
Get Ringo Light for Japan, from $9.99.
Installed once, next to your own SIM. Your eSIM arrives by email in seconds.
- 3 days $9.99
- 2 weeks $21.99
- 30 days $54.99
We sell data eSIMs for now to fund the full Ringo service. Ringo is self funded. Every plan bought here pays for the build of one plan that works everywhere.
Want to keep your own number abroad?
That is the full Ringo service: one plan that works everywhere, with your own number included.
It is a separate product from Ringo Light and it is still being built, so it is not on sale yet. Join the waitlist to hear when it opens.
O2 Travel vs Ringo Light in one paragraph
Japan is where I find the gap easiest to see. Ringo Light is $9.99 against about $28 for three days, $21.99 against about $131 for two weeks and $54.99 against about $281 for a month. O2 Travel still has honest strengths: the same number, calls and texts that need no workaround, and no eSIM slot or setup. For a night in Japan I would buy O2 and think no more of it. For a fortnight on the rail network, or a month, I would buy Ringo Light, which is cheaper and faster.
Price: the same trip at each
I read the O2 travel page on 31 October 2026. It includes Japan among 75 destinations for a fixed £7 a day. A charge covers 24 hours from first use. Three days costs £21 (about $28), two weeks £98 (about $131), a month £210 (about $281). No monthly version is shown. The ECB reference rate of 30 October 2026 turns pounds into dollars here, the latest on 31 October, at £1 = $1.34.
Ringo Light carries US dollar prices, and checkout converts the amount into the buyer's currency before paying. The trips are $9.99, $21.99 and $54.99, each paid once. Savings against the bolt-on are $18.01 for three days, $109.01 for two weeks and $226.01 for a month. One O2 day alone costs most of a Ringo Light long weekend, so O2 wins on ease, not price.
Data and speed at each
O2 calls the bolt-on unlimited, then limits roaming speed to 2Mbps and names no fair use rule. For Japan I expect that to be fine for train apps, Google Maps in Shibuya and LINE messages. Streaming on the way to Kyoto, a video call back to the UK or a tethered laptop in a business hotel will stall. Ringo Light stays at full speed with no daily figure at all. I would read the fair use policy in the Terms before buying.
Calls, texts and your own number
With O2 Travel the phone behaves like home: the page promises unlimited calls to the UK and within Japan, while other countries cost standard roaming rates. Receiving calls and texts does not start the day charge. Banking codes to your UK number still arrive, a point I count for O2. Ringo Light is data only, so calls ride on apps, and your number stays on your own SIM next to it.
Setup and billing
Add the bolt-on with TRAVEL to 23336 or in My O2, where it shows if you already hold it. The £7 starts at your first call, text or data use and ignores any Spend Cap. I would do it from home, which saves fiddling on the platform at Haneda or Narita. Ringo Light is emailed after payment and installs in one QR scan over Wi-Fi; flip data on once you land. An eSIM phone is a must.
What Ringo Light is, and what it is not
I write for Ringo, so weigh this part accordingly. Ringo Light is a data eSIM from Ringo, sold to fund the full Ringo, the single plan that works worldwide. For Japan it has three trips, 3 days at $9.99, 2 weeks at $21.99 and 30 days at $54.99, each unlimited data at full speed, paid once with no renewals.
It has no phone number, so it cannot take over your O2 line for calls, and the phone must take an eSIM. O2 is the simpler path if you want a single bill, and I say that plainly; Ringo Light is the lower price for the same weeks in Japan.
The comparison of the travel eSIM brands for Japan is at /blog/best-esim-for-japan. The card to buy Ringo Light is further up this page, just after the side-by-side table.
Which to pick
- ✓Ringo Light, for most Japanese itineraries. It is $9.99 to $54.99 once, unlimited at full speed, against £7 for each day of use on O2.
- ✓O2 Travel, for a transit night. One £7 day and no installing.
- ✓O2 Travel, without an eSIM slot. It rides on the plan your handset already has.
- ✓Both, for a long assignment. Ringo Light for the data, your own SIM for the calls you need.
Pick by trip
Ringo Light, 3 days, $9.99, against £21 of O2 Travel, about $28.
Ringo Light, $21.99, unlimited at full speed. O2 across fourteen days comes to £98, about $131.
Ringo Light, $54.99, with the laptop on a tether. O2 would run to £210, about $281.
O2 Travel is the easy answer: one £7 charge and your own number.
Stay on O2 Travel, or pair Ringo Light with your own SIM.
Frequently asked questions
How we compared, and our sources
O2, Ringo Light, European Central Bank, Ringo Light
We priced O2 and Ringo Light for Japan on 31 October 2026, all on the same day, in US dollars. Each rival's price comes from its own website where it showed dollars, otherwise from an esimdb.com listing, and every source and its date is listed below. Ringo Light's prices come from the catalogue our checkout charges.
We compare the trips people actually book: a week, two weeks and a month of unlimited data, and a 10 GB bucket. We read each brand's fair use and speed rules and quote them as the brands state them. We did not run speed tests, so this page makes no speed claims for any brand.
Ringo Light is our own product. We put it in the table on the same terms as everyone else, and where a rival is the better buy the page says so.
Left out: Other eSIM brands. Airalo, Holafly, Saily, Nomad and Ubigi sell Japan data too and sit in the wider table at /blog/best-esim-for-japan. This page sets only O2 against Ringo Light. Left out: Other O2 roaming terms. Europe has its own O2 roaming terms and anywhere off the list pays standard rates; I have not priced either here. Japan is on the Travel bolt-on list, so that is the figure used, and the O2 roaming page did not load on the day.
- O2: www.o2.co.uk/international/o2-travel, O2 Travel bolt-on page, read 31 October 2026: £7 a day, charged for the 24 hours from first use, unlimited data capped at 2Mbps while roaming, unlimited calls to the UK and within the destination; the destination is on the page's list of 75 countries. The roaming page at o2.co.uk/international/roaming returned not found on the same day
- Ringo Light: ringoesim.com/japan, the catalogue the checkout charges, read the same day
- European Central Bank: www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml, euro reference rates of 30 October 2026, the latest published on 31 October 2026, used for the dollar figures (£1 = $1.34)
- Ringo Light: our own catalogue, the prices the checkout charges on 31 October 2026.
Written and priced by the Ringo team. Prices change often; if you spot one that has moved, tell us through the contact page and we will update the table.
