eSIMs and how to choose them

Life Technology
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I’ve been wondering how to choose an eSIM plan without getting eSIMs from Chinese telecom companies. This video spend 7000 NTD to try most Japan eSIMs available.

A good observation is that most eSIMs that claims it can allow you to swap networks within Japan will be Chinese telecom products because that is only achievable while data roaming, and it would mean the eSIM is issued by a Hong Kong or China based telecom that is just data roaming in Japan.

I suspect if your eSIM instructs you to turn on data roaming, that would also be a sign that you are using a Chinese telecom product. Instructions for activating povo (KDDI) eSIM did not include turning on data roaming.

Lastly, if you can find out the ICCID for your eSIM before purchase, after the initial two numbers 89, it would be followed by the country code the place that issued the eSIM. So for native Japan eSIM, ICCID would be 8981, for Korea it would be 8982.

Saily basically is using Hong Kong eSIM is roaming in Japan. That means your packets have to travel to Hong Kong first and come back to Japan. That of course has some issues, like delay, and data security issues. Also, Saily is in the same corporation as SurfShark and NordVPN, and with its Asian servers being based in Hong Kong, Saily IPs are VPN IPs, and would often get blocked by banks and other services.

Also, whether eSIM works well depends a lot the base bands that your phone supports. Even if your phone supports all the base bands used by that telecom company, internet speed can still drop off if your phone doesn’t support carrier aggregation for those bands, since some phones will only include CA for bands available for the country where the phone was bought.

For example, these are the base bands used by the 3 major carriers in Japan.

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Most eSIM capable phones in Taiwan don’t support all of them.

My Zenfone 12 for example only supports these:
n1 / n2 / n3 / n5 / n7 / n8 / n12 / n18 / n20 / n25 / n26 / n28 / n38 / n40 / n41 / n48 / n66 / n77 / n78 / n79

Taiwan’s Iphone 17 Pro supports:
n1 / n2 / n3 / n5 / n7 / n8 / n12 / n20 / n25 / n26 / n28 / n30 / n38 / n40 / n41 / n48 / n53 / n66 / n70 / n75 / n77 / n78 / n79

Taiwan’s Google Pixel also don’t have n257 support, so say if you get Rakuten SIM card or eSIM for your Taiwan bought phone, you are going to be stuck at base 5G speed.

Your phone is using CA when it indicates your network mode is 5G+. Many carriers only provide None Stand-Alone CA, which uses 4G with 5G, and then you’d also need to check your phone’s 4G base band support.

Someone made a very comprehensive chart of Japanese carriers’ CA support

Tells you whether you’ll get a Japan IP, Taiwan IP, or Hong Kong IP.

All that to say… it seems way too complicated for the average user to figure out before a trip, but next time I’ll use KDDI or its subsidiary povo’s eSIM.

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Any insights about Nomad multi country eSIMs?

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Mate, you’ve gone so deep into the eSIM rabbit hole you’re now analysing ICCID country codes, carrier aggregation and packet routing like you’re uncovering an international conspiracy. You need a hobby.

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Hopefully eSIM is a one time research kind of thing.

What I do in linguistics (mainly with Old Chinese and Proto-Austronesian), history, baseball, and fair voting are far more geeky, and arguably useless, than this.

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That is extremely helpful, thank you very much. :+1:

@tempogain imo this should be pinned at the top of the International Travel forum.

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Sounds like this is an French-based company, and is a subsidiary of Transatel, which is now owned by the Japanese NTT Group.

The installation instruction for its eSIM does not include enabling roaming.

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Prices also seem reasonable. It is comparable to the prices I saw on DJB.

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your posts might be the highlight of my days at times

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NOW YOU GOT MY COMPLETE ATTENTION

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Data probably routed to Hong Kong, if not China, first.

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I have used them a few times around Asia, like most companies in this region they normally rout through Singapore or Hong Kong, (Single country deal I don’t know as I have always needed and used a regional package).

Mine has always been through Singapore by default, if you look at the package profile you can work out where they are from.
You can always contact customer service before you buy and ask what packages don’t rout through Hong Kong or China (bit shit if your going to China), they are good and will direct you to the correct package.

I think mine was sapphire but you are better checking, if your going to China using a Hong Kong based provider can help bypass the grate firewall to access sites but also not classed as an overseas provider that can get flagged.

Its all about where your going what your doing and the cost/convenience to yourself. I mean if your banking apps are not end to end encrypted anyway what are you doing using them anywhere.

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Nah, that’s a show stopper for me too.

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Honestly if Taiwan mobile providers got there roaming packages sorted out, I wouldn’t have to look around, but sadly thats not the case.

I spoke with someone about this years ago, apparently they cant get good rates with partners overseas, but maybe it has changed now.

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the data package on CHT for JP ran a nice promotion during this summer. like 168 NT per day unlimited roaming (then with CTBC CHT 10% off and also the cashback on the statement). Not the cheapest, but it was fast and very stable, even in rural Aomori prefecture or on the Fuji.

Regionally (AP), the big 3s are still ok-ish if privacy is your concern, but when going like to Europe, boy, it gets expensive. Still having my Italian number, so have EEA+UK roaming for free.

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Used CHT roaming on my trip to Singapore as well. Not much more expensive than China-based eSIM. You could one click buy it from the CHT app.

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Warning: if you are an American and your provider is AT&T, any outside eSims that you purchase abroad (or in the U.S.) will not work. AT&T blocks the competition by making all other eSims incompatible with your device. Instead they will tell you that no worries, they can easily provide international service for the low, low price of $12 a day in roaming fees! And after 12 days, free for the rest of the month! That’s a bargain at $120! Luckily I have a Chinese phone that I haven’t used in years as backup.

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And here I thought SIM-locked / carrier-locked phones were a thing of the 2000s-2010s…

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It’s not the phone itself, it’s the data plan. I’m not giving up my U.S. phone number, I’ve already paid up for the AT&T subscription for the rest of the year.

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So they don’t allow Dual/Multi-SIM? Can you just deactivate your AT&T SIM temporarily when being abroad and later just re-enable it?

It seems like they still allow you to unlock it once you’ve paid your phone:
https://www.att.com/support/article/wireless/KM1008728/

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In the Uk it wasn’t just expensive it was slow, they partnered with EE but it seamed like a throttled service.

If you used CHT roaming in Singapore they partner with Singtel backed up with Starhub and M1, the same as sapphire Esim

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Looks legit.