Short answer
You set an APN manually for a Japan eSIM only when the phone does not already have the settings for that line. Apple says some carriers require you to enter APN settings, and on iOS 16 and iPadOS 15 or later a carrier that supports it can fill them in after the eSIM is set up, so any value you type is the one for this eSIM, not an APN NTT docomo or au gives its own customers.
If the eSIM is installed and still has no data, the line, roaming, and APN checks are covered in Japan eSIM installed but no internet?.
Fact table
As of 2026-10-21
Each claim names its source. The full source list, with the date each page was read, is below.
| Claim | Source |
|---|---|
| Apple says some carriers require you to enter your APN settings to set up your cellular service. You can edit or view the APN on an iPhone or iPad only if your carrier allows it. If you cannot modify the APN settings, Apple says to contact your carrier. Apple says not to edit the APN unless your carrier or mobile device administrator directs you. | Apple Support, APN |
| On iOS 16 and iPadOS 15 and later, Apple says that if your cellular carrier supports it, you can fill APN settings automatically after you set up an eSIM: open Settings, tap Cellular, then tap Cellular Data Network. If you do not see the option to use carrier settings, Apple says to enter your APN settings. | Apple Support, APN |
| To change APN settings, Apple says to tap each field and enter the details from your carrier. The settings should save automatically. Depending on your carrier, you might not be able to change the cellular data settings. If your carrier needs a different APN setting, Apple says you might be able to use a configuration profile with the correct setting. | Apple Support, APN |
| Apple says that unless you are using a configuration profile, updating iOS resets any changes made to your APN settings. If you edit APN settings before updating iOS, they reset to the default values. You might need to reenter your settings after an iOS update. | Apple Support, APN |
| To revert to the carrier's default APN information, Apple says to open Settings, tap Cellular, tap Cellular Data Network, and tap Reset Settings. If you installed a configuration profile, the profile's default information is used instead. If you changed APN settings that a mobile device administrator set from a configuration profile, Apple says to revert on iPhone with that Reset Settings control, and on iPad by removing the configuration profile and adding it again. | Apple Support, APN |
| Apple says that if you are setting up a new device, you might need to reconfigure your APN settings to reconnect with your carrier. | Apple Support, APN |
| Samsung Japan says that when you use an MVNO SIM card or similar, you may need to set an APN, and that the information for that setting comes from the carrier you have a contract with. On a dual-SIM phone, each SIM may need its own settings, and the items on screen can differ by phone model and SIM combination. | Samsung Japan, Galaxy APN |
| On a Galaxy, Samsung Japan's article says to open the Settings app, tap the item it labels 接続, tap the item it labels モバイルネットワーク, tap APN, then tap add. Samsung says モバイルネットワーク appears only when a valid physical SIM or eSIM is recognized. Enter the items the carrier provided, tap the control it labels 保存, and select the APN you added. Samsung says that with some carriers the APN is already shown, and you select that one. | Samsung Japan, Galaxy APN |
| To delete an APN you added, Samsung Japan says to tap the gear icon beside that APN's name, then tap the trash icon it labels 削除. The APN is then removed from the list. | Samsung Japan, Galaxy APN |
| Samsung Singapore says an APN is the name of a gateway that connects the carrier's cellular network to the internet. To reset it, open Settings, tap Connections, tap Mobile Networks, tap Access Point Names, tap More options, and tap Reset to default. Then tap Reset, select SIM Service, and tap OK. Samsung says to skip Connections on older models, and to tap More on older models. | Samsung Singapore, APN |
| NTT docomo's APN page is for using a docomo UIM card in a phone docomo did not sell. For sp-mode on Android, docomo says to set the APN to spmode.ne.jp, the authentication type to unset or none, and the APN protocol to IPv4/IPv6, then save and select that APN. Docomo says that example can differ by Android version and model. The iPhone section of that page points to first-time iPhone setup and does not list an APN. | NTT docomo, APN for a non-docomo phone |
| KDDI's au page covers using an au IC card or au eSIM in a non-au phone. On that page, customers who use packet communications on a non-au Android phone must set the access point, and the page points to au's 5G NET and LTE NET pages for those details. For data on an iPhone, the same page says access point settings are performed automatically when the au IC card is inserted, and that manual settings and a profile download are not required. | au, non-au phone |
| When the Wakamo account page shows installation instructions for an eSIM, an APN section appears only if that eSIM has an APN. The section is titled No mobile data after installing? It says most profiles configure automatically, and to check APN settings if data is unavailable after selecting this eSIM and enabling roaming, and it shows that APN. | Wakamo account |
| The Japan eSIM guide is the write-up for installing a Japan eSIM. It does not name an APN. | Wakamo Japan eSIM guide |
FAQ
When do I type an APN?
Type one when the phone does not already have the settings for that line. Apple says some carriers require you to enter APN settings to set up cellular service, and that on iOS 16 and iPadOS 15 and later a carrier that supports it can fill them after the eSIM is set up. If you do not see the option to use carrier settings, Apple says to enter them. Apple also says not to edit the APN unless your carrier or mobile device administrator directs you. Samsung Japan says an MVNO SIM or similar may need an APN, and that some carriers already show one to select. On a Wakamo account, an APN section appears only when that eSIM has an APN, and that section says most profiles configure automatically.
Which APN do I enter?
Apple says to enter the details from your carrier. Samsung Japan says the information comes from the carrier you have a contract with. NTT docomo's spmode.ne.jp instruction is for a docomo UIM card using sp-mode, on the page for a phone docomo did not sell. au's manual access point is for packet communications on a non-au Android phone with an au line, and au says an iPhone sets the access point automatically when the au IC card is inserted. If the Wakamo account shows an APN for this eSIM, that screen is where that value appears. The Japan eSIM guide does not name an APN.
What if the iPhone will not let me edit the APN?
Apple says you can edit or view the APN only if the carrier allows it. If you cannot modify it, Apple says to contact your carrier. Depending on the carrier, you might not be able to change the cellular data settings. If the carrier needs a different APN, Apple says you might be able to use a configuration profile with the correct setting.
How do I undo an APN I typed?
On iPhone, Apple says to open Settings, tap Cellular, tap Cellular Data Network, and tap Reset Settings. That restores the carrier's default APN information, or the configuration profile's default if a profile is installed. If a mobile device administrator set the APN from a configuration profile, Apple says an iPad reverts by removing that profile and adding it again. On a Galaxy, Samsung Singapore says to open Access Point Names, tap More options, tap Reset to default, tap Reset, select SIM Service, and tap OK. Samsung says to skip Connections on older models, and to tap More on older models. Samsung Japan says you can delete an APN you added from the gear icon beside its name.
Does an iOS update remove an APN I typed?
Apple says that unless you are using a configuration profile, updating iOS resets APN changes to the default values, and that you might need to reenter them after the update. Apple also says that if you are setting up a new device, you might need to reconfigure the APN to reconnect with your carrier.
Why is there no APN menu on a Galaxy?
Samsung Japan says the menu it labels モバイルネットワーク appears only when a valid physical SIM or eSIM is recognized. The items on that screen can differ by phone model and SIM combination.
Sources
Apple Support, APNsupport.apple.com
Some carriers require APN settings to set up cellular service. View or edit only if the carrier allows it. On iOS 16 and iPadOS 15 and later, a carrier that supports it can fill the settings after the eSIM is set up. Enter the details from your carrier. An iOS update resets manual APN changes unless a configuration profile is in use. Reset Settings restores the carrier default, or the profile default if one is installed. A new device might need the APN entered again.
Accessed 2026-10-21.
Samsung Japan, Galaxy APNsamsung.com
An MVNO SIM or similar may need an APN. The information comes from the carrier you contracted with. Each SIM on a dual-SIM phone may need its own settings. The article's path is Settings, then 接続, モバイルネットワーク, APN, and add. モバイルネットワーク appears only when a physical SIM or eSIM is recognized. Some carriers already show an APN to select. An added APN can be deleted from the gear beside its name.
Accessed 2026-10-21.
Samsung Singapore, APNsamsung.com
An APN is the name of a gateway between the carrier's cellular network and the internet. The reset path is Settings, Connections, Mobile Networks, Access Point Names, More options, Reset to default, then Reset, then SIM Service, then OK. Skip Connections on older models. On older models, tap More.
Accessed 2026-10-21.
NTT docomo, APN for a non-docomo phonedocomo.ne.jp
The page is for a docomo UIM card in a phone docomo did not sell. For sp-mode on Android, docomo says to set the APN to spmode.ne.jp. The iPhone section of that page does not list an APN.
Accessed 2026-10-21.
au, non-au phoneau.com
The page covers an au IC card or au eSIM in a non-au phone. It says Android customers who use packet communications must set the access point. On iPhone, it says the access point is set automatically when the au IC card is inserted, and that manual settings and a profile download are not required.
Accessed 2026-10-21.
Wakamo accountwakamo.io
Wakamo product information. When installation instructions are on the account page, an APN section appears only if that eSIM has an APN. The section says most profiles configure automatically, and to check APN settings if data is unavailable after selecting this eSIM and enabling roaming.
Accessed 2026-10-21.
Wakamo Japan eSIM guidewakamo.io
Wakamo product information. The Japan eSIM guide is the write-up for installing a Japan eSIM. It does not name an APN.
Accessed 2026-10-21.