Voicemail is a service that records a caller's voice message when you cannot answer the phone. On landlines it is normally a recording function built into the handset, while on mobile phones carriers usually provide it as a service that records the message on the network side.
Mobile voicemail can capture a message on the network even when the handset is switched off or out of range, which is the main difference from a landline answering machine. Playback normally means placing a call to a dedicated number yourself: with NTT Docomo's voicemail service you dial 1417 to listen. Stored messages are erased automatically after a set period - 72 hours in Docomo's case, with each message running up to three minutes and up to 20 messages held (as of August 2026). Retention time and message limits differ by carrier and plan, so it is worth checking what your own contract allows before you rely on it.
How it is billed depends on the carrier and the plan: sometimes it is a paid monthly option you have to sign up for, and sometimes it is bundled into the plan itself. NTT Docomo's voicemail service requires sign-up and costs 330 yen per month including tax (as of August 2026). Because listening to messages means placing a call yourself, check how playback calls are charged as well as the monthly fee.
From the 2010s onward, more people switched to free "incoming call notification" services that send an SMS instead of taking a message. Features such as the iPhone's visual voicemail, which lists messages so you can play back the one you want, and automatic speech-to-text transcription have also appeared. As a defense against nuisance calls, setting a short ring time so that voicemail picks up early makes the caller state their business, which helps you judge who is calling. Calls behind bank transfer fraud are said to avoid leaving a recording, and once voicemail answers, you decide whether to pick up while anything the caller says stays on your side. Letting unknown numbers go to voicemail and deciding whether to call back only after listening also makes it easier for a household to handle calls the same way. How to Handle Anonymous Calls is worth reading alongside this.