Japanese Phone Number Regex for Java

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching japanese phone number, ported and verified for Java. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.

Java Implementation

// Japanese Phone Number
// ReDoS-safe | RegexVault — Localization > Phone Numbers

import java.util.regex.Pattern;

public class JapanesePhoneNumberValidator {
    private static final Pattern PATTERN =
        Pattern.compile("^(?:(?:\\+81[\\s.-]?|0)(?!0)(?=[0-9\\s.-]{10,13}$)(?:[1-9][0-9]{0,3}[\\s.-]?[0-9]{2,4}[\\s.-]?[0-9]{4})|(?:\\+81[\\s.-]?|0)(?!0)(?:[1-9][0-9]{3}[\\s.-]?[0-9]{1,2}[\\s.-]?[0-9]{4}))$");

    public static boolean validate(String input) {
        return PATTERN.matcher(input).matches();
    }

    // Example
    public static void main(String[] args) {
        System.out.println(validate("+81 3 1234 5678")); // true
    }
}

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Phone Numbers category and carries a ReDoS-safe certification. That matters for Java developers because critical in Java applications since the JVM regex engine uses backtracking and is susceptible to ReDoS without careful pattern design. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Japanese area codes: 03 (Tokyo), 06 (Osaka), 011 (Sapporo). Mobile numbers start with 070, 080, 090 (in domestic format). IP phone (050). +81 replaces the leading 0. Total 10-11 digits.