If your app sends SMS worldwide, Israel has a few quirks that silently break validation, inflate costs or annoy users. This is a short checklist. The full guide is linked at the end.
1. Number format
Israeli mobile numbers have 10 digits locally and start with 05. For international systems, drop the leading 0 and add 972:
050-123-4567 / 0501234567
E.164
+972501234567
Not every 05 number is Israeli mobile. The Israeli mobile prefixes are 050, 051, 052, 053, 054, 055, 058. 056 and 059 belong to Palestinian networks that share +972, and 057 is no longer in use. So avoid 05[0-9] and use an explicit list:
^(?:\+972|972|0)(?:50|51|52|53|54|55|58)\d{7}$
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(Strip spaces and dashes first.) Israel also has number portability, so the prefix doesn’t tell you the carrier.
2. Hebrew means UCS-2, and that changes the math
Encoding Single SMS Per segment when split GSM-7 (Latin) 160 153 UCS-2 (Hebrew) 70 67One Hebrew letter, emoji, curly quote or long dash switches the whole message to UCS-2. Budget by segments, not characters. Watch for invisible direction marks copied from word processors: they count as characters too.
The phone handles right-to-left display, so Hebrew mixed with English, numbers and links renders fine without adding direction marks.
3. Sender ID
Common options are a mobile number (recipients can reply), a landline number (they can call back, not text back), or an alphanumeric name in English letters and digits, up to 11 characters (no replies). If you need replies, use a mobile or virtual number. Check your provider’s verification requirements before the first send.
4. Timing
- Time zone:
Asia/Jerusalem(UTC+2 / UTC+3 in summer). DST dates don’t always match Europe or the US, so schedule by IANA zone. - Weekend: Friday–Saturday. Shabbat runs from Friday evening to Saturday night, and the business week is Sunday–Thursday.
- Jewish holidays follow the Hebrew calendar, so their Gregorian dates move every year.
5. OTP messages
Put the code first (lock-screen preview), name the service, state the purpose and validity, and don’t include a link:
[Service]: 458213 is your password reset code. Valid for 5 minutes. Didn't request it? Ignore this message.
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6. Delivery reports
“Accepted” is not “delivered”. Poll or subscribe to delivery reports (DLR), and treat “no final status within N seconds” as a failure so users can retry.
7. Marketing messages
Israeli law regulates advertising messages (prior consent, sender identification and an easy opt-out are among the requirements). Check with local counsel before automating marketing sends.
Full guide with more detail on sender IDs, DLR statuses and replies: SMS in Israel: A Developer’s Guide
Disclosure: I’m the CEO of Global SMS, an Israeli SMS gateway.