Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
  • Effective date searches are available only for US area codes. Our sources for non-US NPA-NXX data do not provide this information.
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NPA: 424 [Rate centres in NPA 424] [Dial plan for NPA 424]

NXX: 556

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
424-556 A Santa Monica: Santa Monica DA CA   6529 T-MOBILE USA, INC. 730   2025-08-01   
424-556 8 Santa Monica: Santa Monica DA CA   6529 T-MOBILE USA, INC. 730   2025-08-01   
424-556 9 Santa Monica: Santa Monica DA CA   6529 T-MOBILE USA, INC. 730   2025-08-01   

Last updated: Wed, 18 Jun 2025 02:30:00 UTC

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