Save numbers for the way you will call

Osaka’s guide explains domestic and international calling formats and points users to provider information for mobile-phone contracts. When saving an important number, record the service name, department and the format needed from your device. A number written for a local landline call may need different formatting when used internationally.

For a mobile contract, ask the chosen company for its current identity and address-document requirements. The city guide identifies residence documentation and evidence of address as relevant. Check accepted payment methods and how long setup takes before making the number essential to another application.

Compare the whole service

Write down your expected data use, domestic calls, international calls and the places where you need coverage. Ask whether the quoted price includes the handset and any options, and how the arrangement changes after a promotional period. Review cancellation, number-transfer and device compatibility conditions in the actual contract.

Keep the provider’s official support contact and account-access method securely. Do not share verification codes or leave identity-document copies in a public message. Before an important call, prepare a short explanation, your reference number and the questions you need answered. Record the next action afterwards. If calling a public service, check language availability and hours first, and avoid assuming an online inquiry has the same effect as submitting the required application.

Adapted and rewritten by Japanese.Pink from the City of Osaka’s How to make a phone call. The wording and organization have been edited. Source checked: 9 November 2026.