Laravel localization in Japanese 日本語

Locale codes

Set the base locale in config/app.php. For regional variants, Japanese commonly uses: ja_JP

// config/app.php
'locale' => 'ja',
'fallback_locale' => 'en',

// Or switch at runtime
App::setLocale('ja');

Plural rules: what Japanese actually needs

CLDR defines 1 cardinal category for Japanese. The sample numbers below were computed by ICU for this exact locale:

Laravel's trans_choice() maps numbers to 1 pipe-separated form for this locale:

// lang/ja/messages.php
'items' => ':count'

// Usage
trans_choice('messages.items', $count, ['count' => $count]);

This language has no grammatical plural, so a single form covers every number.

Try any number live in the pluralization tester.

Localized dates with Carbon

Real output for Japanese (ja locale), generated by Carbon for March 21, 2026:

$date = now()->locale('ja');

$date->translatedFormat('l, j F Y');
// "土曜日, 21 3月 2026"

$date->isoFormat('LLLL');
// "2026年3月21日 土曜日 14:30"

$date->isoFormat('L');
// "2026/03/21"

$date->subDays(3)->diffForHumans();
// "3ヶ月前"

What to watch out for in Japanese

• No spaces between words; line breaking follows character-based rules, not word boundaries.
• Honorific registers (keigo) matter: polite -masu/desu forms are the norm for UI copy.
• No grammatical plural or gender; particles (は, が, を) mark grammatical roles, so word order around placeholders differs from English.
• Dates are written year-first (2026年3月1日) and full-width punctuation (。、) is standard.

Framework strings already translated

Laravel's own validation, auth and pagination strings are maintained in Japanese by the open-source Laravel-Lang project (MIT). Install them, then manage your app's own strings live:

composer require laravel-lang/common --dev
php artisan lang:add ja
php artisan lang:update