Send SMS to Japan
from $0.0580/msg

Reach 78 million Japanese subscribers via NTT DoCoMo (38%), KDDI (28%), SoftBank Mobile (25%), and Rakuten Mobile (9%). Send with 72ms median latency and 99.4% delivery success. No KYC at signup—pay with Bitcoin, USDT, Ethereum, Litecoin, Monero, or Solana. Crypto-native A2P SMS for Japan, starting at just $0.0580 USD per message.

Why Japanese Characters Segment Cut Your Message Budget by Up to 3× — UCS-2 vs. GSM-7 Encoding

If you are sending SMS in English, each message grants you 160 characters before the SMS network splits your text into multiple segments. But Japanese—whether hiragana (ひらがな), katakana (カタカナ), or kanji (漢字)—triggers UCS-2 encoding, which reduces the character limit to just 70 per segment. A promotional message announcing a sale in English might fit comfortably in one segment; the identical message translated to Japanese will require two or even three segments, and you will be charged accordingly.

For example, consider a 150-character promotional text in English announcing a 20% discount at a restaurant. That message fits entirely into one SMS segment at GSM-7 encoding. Translate the same offer to Japanese—"レストランで20%割引キャンペーン実施中。今すぐお得な食事を楽しみましょう。"—and you now have a 70-character message that still requires only one segment. But a 210-character campaign (e.g., offering a discount plus additional terms and a link) will split across two segments in English but expand to three segments in Japanese, nearly tripling your per-message cost.

When budgeting for Japanese SMS campaigns, always plan for 2–3× the segment count compared to equivalent English text. Test longer messages in advance using your API sandbox to understand real-world segment boundaries. Mixed-script messages (English and Japanese together) also trigger UCS-2 encoding for the entire message, so even a short English phrase embedded in Japanese text will force the entire SMS into UCS-2, reducing your character budget from 160 to 70.

APPI Compliance, Consent Frameworks, and Quiet Hours in Japan

Japan's Act on Protection of Personal Information (APPI), which took effect in April 2022, is the nation's primary data protection framework. For A2P SMS senders, the APPI mandates that all marketing SMS require explicit prior written or electronic consent before transmission. A recipient's mere inaction or silence does not constitute consent; you must obtain affirmative, unambiguous opt-in before sending promotional messages.

Transactional SMS are different. Order confirmations, password resets, account balance alerts, and shipping notifications are generally considered implied by the subscriber agreement itself and do not require separate APPI consent. However, any SMS that promotes a product, service, or offer—even if it includes transactional elements—should be treated as marketing and must have prior consent on file.

The Ministry of Internal Affairs and Communications (MIC) (https://www.soumu.go.jp/english/) enforces APPI. The regulator has published enforcement guidance clarifying consent requirements for marketing SMS. While specific penalties are determined on a case-by-case basis, senders who ignore consent obligations face administrative guidance, reputational damage, and escalated enforcement action. All marketing SMS must include a clear, easy opt-out mechanism (reply STOP or visit a URL).

Quiet hours: Send marketing SMS only between 09:00 and 21:00 Japan Standard Time (JST). Avoid sending marketing messages on national holidays and during the Golden Week period (late April), when consumer engagement drops and unsubscribe complaints spike. Transactional SMS are exempt from quiet-hour restrictions.

Mobile Operators and Interconnect Coverage in Japan

Japan's telecom market is dominated by four operators, each with direct SMS interconnect:

All four operators support A2P SMS with numeric sender IDs only (no alphanumeric IDs permitted). Reaching all four operators simultaneously requires either a network aggregator (like smsroute) or separate agreements with each carrier. smsroute maintains direct relationships with all four, ensuring comprehensive coverage at a single API endpoint.

How to Send SMS to Japan in 3 Steps

Step 1: Create a Free smsroute Account

Visit smsroute.cc, click "Sign Up," and fill out the registration form. No phone verification, no ID upload, no corporate documents. You will receive instant API credentials (API key and secret) via email, plus a live API endpoint URL.

Step 2: Top Up Your Balance with Cryptocurrency

Log in to your dashboard. Navigate to "Billing" → "Add Credit." Select your preferred cryptocurrency:

• Bitcoin (BTC)
• USDT (TRC-20 preferred)
• Ethereum (ETH)
• Litecoin (LTC)
• Monero (XMR)
• Solana (SOL)

Minimum top-up is $5 USD. Once the blockchain confirms your transaction (typically 1–3 confirmations), your balance updates immediately in the dashboard.

Step 3: Send SMS via REST API to E.164-Formatted Numbers

Use the smsroute REST API to send SMS. Target Japanese mobile numbers in E.164 format: +81 9X XXXX XXXX, where 9X is 90, 80, or 70. Example: +81 9012345678.

cURL Example:

Python Example:

The API will validate the destination number, calculate the number of SMS segments (factoring in UCS-2 encoding for Japanese text), deduct the appropriate number of credits, and return a message ID (in JSON) within 100 milliseconds. You can then track delivery status via webhooks or polling the status endpoint.

curl -X POST https://api.smsroute.cc/send \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+81 9012345678",
    "from": "123456",
    "text": "ご注文ありがとうございます。配送予定: 2024年1月15日"
  }'

import requests

api_key = "YOUR_API_KEY"
url = "https://api.smsroute.cc/send"

headers = {
    "Authorization": f"Bearer {api_key}",
    "Content-Type": "application/json"
}

payload = {
    "to": "+81 9012345678",
    "from": "123456",
    "text": "ご注文ありがとうございます。配送予定: 2024年1月15日"
}

response = requests.post(url, json=payload, headers=headers)
print(response.json())

import fetch from "node-fetch";

const apiKey = process.env.SMSROUTE_API_KEY;

const res = await fetch("https://api.smsroute.cc/v1/sms/send", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${apiKey}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    to: "+815551234567",
    from: "smsroute",
    text: "Your verification code is 384921",
  }),
});

console.log(await res.json());