Comparison

PREP(プレップ) vs Japan Alerts

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

PREP(プレップ)

This app provides real-time disaster information based on your current location, including alerts for earthquakes, tsunamis, and heavy rain. It helps you plan for disasters by allowing you to set action plans and share information with family members. The app also offers guidance during emergencies to ensure safe actions.

Highlights
  • Real-time disaster information by location
  • Disaster action planning
  • Emergency guidance
  • Family information sharing
  • Various disaster alerts (earthquake, tsunami, rain, etc.)
  • Precipitation forecast timeline
Read full description

PREP is currently available in Japanese only. If you have Yurekuru Call and prefer English, we recommend keeping your current version. Thank you for your patience and we are working hard to support English as soon as possible. ◆ PREPのポイント  - 現在地と連動してリアルタイムな災害情報を表示します。  - 災害時の行動方針をあらかじめ決めておくことができます。  - 災害発生時、安全な行動を取れるようにガイダンスを表示してサポートします。 ◆ PREPでできること 1.さまざまな災害に対応 災害情報を届ける「ライブ」機能 地震・津波・台風・大雨・噴火など、さまざまな災害情報や避難情報に対応。 現在地に応じたリアルタイムな情報を届けます。 最大24時間先までの降水情報を表示するタイムライン機能も搭載しています。 2.知るから、行動するへ 防災計画を立て、災害時の行動を支援する「アクション」機能 災害発生時にどのような行動を取ればいいかをあらかじめ検討したり、避難場所や防災用品を登録することができます。 大規模災害が予想される場合は、事前に登録した情報に応じて避難のガイダンスを表示し、災害発生時の行動をサポートします。 同居の家族最大6人と情報共有 ファミリープラン(有料)に登録すると、事前に検討した防災計画や、災害発生時の安否を同居の家族と共有できます。 ◆ PREPがあつかう災害情報 - 地震情報(緊急地震速報) - 津波情報 - 噴火速報・警報 - 降水情報 - 指定河川洪水予報 - 台風情報 - 大雨危険度(土砂災害、浸水、洪水) - 竜巻情報 - 雷情報 - 避難情報 ◆ 有料プラン [ 料金形態 ] - プレミアムプラン:120円/月 - ファミリープラン(6人まで):360円/月 プレミアムプラン初回購入の方は1ヵ月無料でお試しいただけます。無料トライアル期間終了後は月額(¥120)でご利用いただけます。 プレミアムプラン、ファミリープランは自動継続課金機能(Auto Renewable Subscription)を利用しています。 自動更新される際の課金は、有効期限の終了後の24時間以内におこなわれます。 ◆ 有料プランでできること 1. チーム(ファミリープランのみ) 同じ住所にお住いの方でひとつのチームを作ることができます。チームリーダーを含めて6人まで参加可能です。 プランで決めた自分の避難場所や防災用品のリストを、チーム内で共有しましょう。 災害発生時には、自分の安否をチームに知らせることができます。(Googleパーソンファインダーへ連携もできます) 2. 超高速プッシュ通知 有料プランユーザー向けには優先して災害情報をいち早く配信します。 ※端末の通信状況によって通知が届くまで数秒かかることがあります。あらかじめご了承ください。 3. 地震一覧を直近50件まで表示 無料版では直近10件のみ表示される地震一覧が、最大50件まで表示できます。 4. 複数地点設定 有料プランでは設定地点を3箇所登録することができます。 ※通知の優先順位は、現在地、地点A、地点B、地点Cの順になります。 5. 広告非表示 有料プランでは広告が非表示になり、より快適にご利用いただけます。 [ 自動更新の確認・解約方法 ] 自動更新の確認・解約は、設定App > 自分の名前 > サブスクリプションからおこなえます。 *「サブスクリプション」が表示されない場合 設定App > iTunes と App Store > 自分の Apple ID > Apple ID を表示(サインイン) > サブスクリプション 有効期間終了の24時間以上前に「サブスクリプションをキャンセルする」を選択すると自動更新を停止することができます。 自動更新される際の課金は、有効期限の終了後の24時間以内におこなわれます。 [ 利用規約 ] https://www.service.rcsc.co.jp/prep-policy [ プライバシーポリシー ] https://www.rcsc.co.jp/privacy

About

Japan Alerts

Receive real-time alerts for earthquakes, tsunamis, volcanoes, and typhoons directly from Japan's official meteorological agency. Features include S-wave countdowns, municipality-level evacuation orders, and multi-language support for essential information.

Highlights
  • Real-time earthquake, tsunami, volcano, and typhoon alerts
  • S-wave countdown for shaking arrival
  • Municipality-level evacuation orders
  • Multi-language translation of alerts and place names
  • Interactive map with hazard layers and shelters
  • Family safety group and check-in features
  • Offline access to shelter information
Features
Read full description

Japan Alerts delivers real-time earthquake, tsunami, volcano, typhoon, and all kinds of evacuation alerts from the Japan Meteorological Agency (JMA), translated into 12 languages. WHO IS THIS APP FOR? - Residents and expats who need alerts in their own language - Travelers — add your destinations (up to 6 in Premium) and arrive prepared - Anyone with family or a loved one in Japan - Families who want a shared earthquake safety plan - Anyone fascinated by Japanese seismology and volcanology REAL-TIME ALERTS - Earthquake alerts with Shindo intensity and magnitude - S-wave countdown on emergency alerts: how many seconds before the shaking reaches you - Tsunami warnings with expected wave height and affected coastline - Municipality-level evacuation orders for every hazard — floods, landslides, storm surge and more — by warning level, in plain language - Volcanic eruption bulletins, typhoon tracking and severe-weather alerts 10 LANGUAGES Not just the app: alerts and place names are translated — nothing vital stays in Japanese only. Note: shelter names, addresses and place names are provided in English and/or romaji, not in the app language. Available in English, Japanese, French, Chinese, Korean, German, Spanish, Italian, Portuguese, and Russian. FREE — THE SAFETY ESSENTIALS - Alerts for moderate quakes (Shindo 4+) near you, and strong quakes (Shindo 6-) anywhere in Japan - 98,000+ official evacuation shelters with names and addresses in English/romaji, plus walking directions and offline access - Interactive map: epicenters, affected areas, and shelters (earthquake, tsunami, flood, fire) - A family safety group, "I'm safe" check-in, and a shared map - 100 years of seismic history in an animated time-lapse, plus statistics - Distinct, customizable alert sounds and a quiet night mode PREMIUM — GO DEEPER - Watch up to 7 places at once: your home plus 6 custom zones anywhere in Japan - Set your own Shindo threshold per zone — be alerted before it gets serious - Hazard maps across all 47 prefectures: flood, tsunami, landslide, liquefaction, volcanic and more (free: your home prefecture, one hazard type only) - No ads - Traveling to Osaka next month? Add it as a zone before you go. INTERACTIVE MAP & SHELTERS - Epicenters, affected areas, hazard layers and volcanoes at a glance - Filter shelters by type: earthquake, tsunami, flood, fire - Check in at a shelter and see real-time occupancy from other users STAY PREPARED - One-tap access to emergency services (110 police, 119 fire, 118 coast guard) - Post-quake analysis for M6+ events: your distance to the epicenter, S-wave travel time, energy released - Detailed preparedness guidance by hazard type ABOUT JMA The Japan Meteorological Agency operates over 4,000 seismic stations and monitors all 111 active volcanoes in Japan. This app uses JMA public data but is not affiliated with JMA or the Japanese government. It is not a substitute for J-Alert or any official warning system — in an emergency, always follow your local authorities. Free with ads. Premium unlocks custom watch zones, per-zone thresholds, and nationwide hazard maps, and removes all ads. Safety shouldn't be a luxury — Premium is priced to stay accessible to everyone. SUBSCRIPTION INFORMATION Japan Alerts offers an optional auto-renewable subscription. • Subscription automatically renews unless cancelled at least 24 hours before the end of the current period. • Payment will be charged to your Apple ID account at confirmation of purchase. • Your account will be charged for renewal within 24 hours prior to the end of the current period. Privacy Policy: https://www.index64.com/japan-alerts/privacy-policy/ Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

PREP(プレップ)4 screens
Japan Alerts4 screens

Verdict

The call

The clearest difference is rating: Japan Alerts at 4.4 against PREP(プレップ)'s 2.3. Japan Alerts also leads on update cadence (every 5 days vs every 6 weeks) and ratings volume (18 vs 6). PREP(プレップ)'s advantage is review sentiment (29% vs 20%). On price, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. PREP(プレップ) sells 2 in-app purchases, starting at $0.99 per month and Japan Alerts sells 1 in-app purchase, starting at $7.99 per year. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Japan Alerts holds the better App Store score, 4.4 against 2.3. Both are backed by a comparable volume of ratings — 6 and 18 respectively. Written reviews complicate that: 29% of PREP(プレップ)'s written reviews are positive against 20% of Japan Alerts's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

PREP(プレップ) ships an update every 6 weeks, Japan Alerts every 5 days. The most recent releases landed on October 14, 2026 and October 11, 2026 respectively.

Scorecard4 real differences · 6 level
PREP(プレップ) versus Japan Alerts: the parameters behind the verdict, then further details
ParameterPREP(プレップ)Japan Alerts
PriceFreeFree
Rating2.3 (6 ratings)4.4 (18 ratings) — better
Positive reviews29.1% of reviews — better20.0% of reviews
Number of ratings618 — better
Update frequencyEvery 6 weeksEvery 5 days — better
AdsYesYes
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPod — betteriPhone, iPod
Requires iOS15.0 — better15.1
Further details — not scored
Size90 MB127 MB
Age rating4+4+
DeveloperRC Solution Co.Itchigoo

Customer experience

PREP(プレップ)

All ratings6 ratings
Positive33.3%
Neutral0.0%
Negative66.7%
Written reviews189 reviews
Positive29.1%
Neutral10.1%
Negative60.8%

Japan Alerts

All ratings18 ratings
Positive83.3%
Neutral5.6%
Negative11.1%
Written reviews5 reviews
Positive20.0%
Neutral0.0%
Negative80.0%

In-app purchases

2 purchases

PREP(プレップ)

Subscriptions2
  • PREP Premium Service1 Month trial$0.991 Month
  • PREP ファミリーサービス$3.491 Month
1 purchases

Japan Alerts

Subscriptions1
  • Annual Subscription$7.991 Year

Questions

Is PREP(プレップ) free?
PREP(プレップ) is free to download, with in-app purchases available.
Is Japan Alerts free?
Japan Alerts is free to download, with in-app purchases available.
Which has better reviews, PREP(プレップ) or Japan Alerts?
Japan Alerts is rated higher. PREP(プレップ) averages 2.3 out of 5 from 6 ratings, while Japan Alerts averages 4.4 from 18 ratings.
Do PREP(プレップ) or Japan Alerts have ads?
Both PREP(プレップ) and Japan Alerts show ads.
Which is updated more often, PREP(プレップ) or Japan Alerts?
PREP(プレップ) ships an update every 6 weeks, and Japan Alerts every 5 days. Most recently, PREP(プレップ) was updated on October 14, 2026 and Japan Alerts on October 11, 2026.

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