631
Covers Suffolk County, New York
In service since 1999
Overlay with 934
City facts
Islip area codes
Area codes for Suffolk County, New York: history, overlays and how to dial.
631934
Islip uses area codes 631 and 934. Because more than one area code serves the same area, local calls need all ten digits.
About these area codes
934
Covers Suffolk County, New York
In service since 1999
Overlay with 631
How to call a number in Islip
Inside the US
1 (631) 555-0123Dial 1, the area code, then the seven-digit number.Local call
(631) 555-0123Overlay area: always include the area code.From outside the US
+1 631 555 0123Use your country's exit code or +, then 1 for the US.Islip is on Eastern Time (ET); check the time before calling from another zone.
Other cities that share these codes
Nearby area codes
| Area code | Used in | Distance |
|---|---|---|
| 516 | Oyster Bay | 14 mi |
| 363 | Oyster Bay | 14 mi |
| 203 | Stamford | 31 mi |
| 475 | Stamford | 31 mi |
| 914 | White Plains | 35 mi |
| 201 | Jersey City | 42 mi |
| 551 | Jersey City | 42 mi |
| 862 | Newark | 49 mi |
Islip quick facts
Islip was incorporated in 1683. It is named for Islip, Northamptonshire.
Incorporated1683
CountySuffolk CountyNew York
Area codes631, 934Population17,224Census ACS estimateZIP codes211706, 11751Elevation7 ft2 m
Time zoneEastern TimeET
Dates, namesake and elevation from Wikipedia: Islip, New York and Wikidata (checked 2026-11-08); population and ZIP codes from the U.S. Census Bureau.
Questions
What area code is Islip?
Islip uses area codes 631 and 934. Because more than one area code serves the same area, local calls need all ten digits.
When did area code 631 start?
Area code 631 dates from 1999.
When did area code 934 start?
Area code 934 dates from 1999.
Do I need to dial the area code for local calls in Islip?
Yes. 631 and 934 share the same area as an overlay, so every local call needs the area code plus the seven-digit number (ten digits).
What time zone is area code 631 in?
Islip is on Eastern Time (ET).
What other cities use area code 631?
Other cities in this network that share 631 and 934 include Huntington, Brookhaven.
Sources: Area codes 631 and 934, Area codes 631 and 934 (Wikipedia) and Wikidata, checked 2026-11-08. Numbering plans change; the North American Numbering Plan Administrator is the official record.