Area Code +81-503-(5810000...5819999) located in VoIP, more detail is as below. Place International Dialing Code : 81 International Prefix : 010 National Prefix : 0 National Destination Code : 503 Subscriber Number From : 5810000 Subscriber Number To : 5819999 National Destination Code Length : 3 Uses National Destination Code : Yes National Significant Number Length : 10 Number Type : V (VoIP, Location Independent fixed land line) Carrier Name : NTT Communications Click here to buy Japan Area Code Database Other Information Language Code : ja (Japanese) Country Number : 392 (Japan) Country Code : JP (Japan) City : VoIP Timezone : Asia/Tokyo Coordinated Universal Time : +09:00 Daylight Saving Time : No National Significant Number Minimum Length : 10 Latitude : None Longitude : None ‹ previous : +81-503-(5800000...5809999) next › : +81-503-(5820000...5829999) Dialling Instructions For trunk calls: 0 503 5810000 (Trunk Code + National Destination Code + Subscriber Number) For international calls: 010 81 503 5810000 (International Prefix + International Dailing Code +National Destination Code + Subscriber Number) Telephone Number List 5810000 ~ 5819999 (Count: 10,000) Example: +81-503-5810000 / 01081-503-5810000 (0503-5810000 / 0-503-5810000) +81-503-5810001 / 01081-503-5810001 (0503-5810001 / 0-503-5810001) +81-503-5810002 / 01081-503-5810002 (0503-5810002 / 0-503-5810002) +81-503-5810003 / 01081-503-5810003 (0503-5810003 / 0-503-5810003) +81-503-5810004 / 01081-503-5810004 (0503-5810004 / 0-503-5810004) ...+81-503-xxxxxxx / 01081-503-xxxxxxx (0503-xxxxxxx / 0-503-xxxxxxx) ...+81-503-5819995 / 01081-503-5819995 (0503-5819995 / 0-503-5819995) +81-503-5819996 / 01081-503-5819996 (0503-5819996 / 0-503-5819996) +81-503-5819997 / 01081-503-5819997 (0503-5819997 / 0-503-5819997) +81-503-5819998 / 01081-503-5819998 (0503-5819998 / 0-503-5819998) +81-503-5819999 / 01081-503-5819999 (0503-5819999 / 0-503-5819999)