Best Japan eSIM for iPhone

This article contains affiliate links. We may earn a commission at no additional cost to you.

Affiliate disclosure: This article contains affiliate links. If you buy through an eligible link, we may earn a commission at no extra cost to you. This does not affect our research-based assessment.

Last checked: 2026-08-13

Check your iPhone before comparing Japan eSIMs

Start with eligibility, not plan size. Apple says travel eSIM use requires an iPhone XS, iPhone XS Max, iPhone XR, or later. It also says that using two carriers requires an unlocked iPhone unless both plans are from the same carrier. [source-support-apple-com-1] [source-support-apple-com-2]

On the iPhone, go to Settings > General > About and look at Carrier Lock. “No SIM Restrictions” indicates that the phone is unlocked. [source-support-apple-com-1]

Apple also says travel-eSIM setup requires Wi-Fi or a hotspot, subject to regional eSIM-only exceptions. Arrange a connection before beginning installation. [source-support-apple-com-1]

The key iPhone setup: keep your home line, use the Japan eSIM for data

A travel data plan can be used as the cellular-data line while your home line remains in use. Apple notes that the home eSIM may still incur roaming fees, so keeping a home line active does not by itself prevent charges. [source-support-apple-com-1]

For a Japan travel eSIM, select the travel eSIM as the Cellular Data line and review the home line’s roaming setting. Apple documents that Data Roaming can be turned on or off for a selected cellular line. [source-support-apple-com-4]

Mobile Data Switching warning: Do not assume the iPhone will always stay on the Japan data line. Ubigi specifically instructs customers not to allow Mobile Data Switching because it could lead to roaming on the local carrier. If avoiding home-line roaming matters, check this setting before relying on mobile data. [source-cellulardata-ubigi-com-6]

Remember that an iPhone uses one cellular data network at a time. [source-support-apple-com-2]

Comparison: documented iPhone considerations

Why hotspot support and APN help matter

Personal Hotspot uses the line selected for cellular data when two SIMs are configured. However, Apple says hotspot availability and connected-device limits depend on the carrier and iPhone model. [source-support-apple-com-3]

Ubigi provides instructions for sharing its connection through Personal Hotspot. It also says that a greyed-out Personal Hotspot option may require APN registration first, and directs customers to Customer Service if the issue continues after APN checks. [source-cellulardata-ubigi-com-7]

That makes hotspot documentation and APN troubleshooting meaningful comparison criteria, especially if you expect to connect a laptop or another device. Do not treat hotspot availability as automatic simply because an eSIM is installed. [source-support-apple-com-3] [source-cellulardata-ubigi-com-7]

Provider notes

Ubigi: strongest documented setup and troubleshooting fit

Ubigi’s Japan page lists KDDI and NTT DoCoMo under its Japan networks and says its plans require an eSIM-enabled, network-unlocked device. It lists iPhone XR, XS, XS Max, and later iPhone models among compatible iOS devices on that page. [source-cellulardata-ubigi-com-5]

Its iPhone instructions use an emailed QR code, then Continue and Add Data Plan. Ubigi instructs users to choose Ubigi for Mobile Data. It identifies its travel eSIM line as data-only and advises retaining the local carrier for FaceTime and iMessage selection. [source-cellulardata-ubigi-com-6]

Drawback: the specific Japan plan price, data allowance, and validity shown on Ubigi’s product page are volatile and must be checked again before publication or purchase. [source-cellulardata-ubigi-com-5]

Saily: compare current package terms carefully

Saily’s Japan page currently displays 1 GB for 7 days, plus 3 GB, 5 GB, 10 GB, and 20 GB options for 30 days. It also displays a 15-day unlimited plan. [source-saily-com-1]

The same page states that its unlimited plan includes 5 GB per day without a speed limit, followed by unlimited data at up to 1 Mbps. These are volatile published terms, not a permanent recommendation; recheck them immediately before publication or purchase. [source-saily-com-1]

Saily’s help centre states that a package expires when its validity ends or its data allowance is used up, and that packages generally have 7-day or 30-day validity periods. [source-support-saily-com-2]

Drawback: the supplied documentation does not establish Saily-specific hotspot support or an APN troubleshooting route. If tethering is essential, confirm those details directly before buying.

Check Saily’s current Japan eSIM options

Bottom line

Choose Ubigi if documented iPhone installation, keeping the home line for FaceTime and iMessage selection, Mobile Data Switching guidance, hotspot instructions, and an APN checkpoint are your priorities. [source-cellulardata-ubigi-com-6] [source-cellulardata-ubigi-com-7]

Consider Saily if you want to compare its currently published package formats, but verify all plan terms immediately before committing and confirm hotspot support separately if you need it. [source-saily-com-1]

Whichever provider you choose, first confirm that the iPhone is unlocked, set the Japan eSIM as the cellular-data line, review Data Roaming for the home line, and do not overlook Mobile Data Switching. [source-support-apple-com-1] [source-support-apple-com-4] [source-cellulardata-ubigi-com-6]

Methodology

This is a remote, research-based guide based on the cited official documentation and current published terms. We compared documented setup states, device instructions, roaming guidance, APN checkpoints, and provider-specific qualifications. We did not physically test, purchase, install, activate, or use any eSIM.