Area Code +81-503-(3990000...3999999) 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 : 3990000 Subscriber Number To : 3999999 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-(3980000...3989999) next › : +81-503-(4000000...4009999) Dialling Instructions For trunk calls: 0 503 3990000 (Trunk Code + National Destination Code + Subscriber Number) For international calls: 010 81 503 3990000 (International Prefix + International Dailing Code +National Destination Code + Subscriber Number) Telephone Number List 3990000 ~ 3999999 (Count: 10,000) Example: +81-503-3990000 / 01081-503-3990000 (0503-3990000 / 0-503-3990000) +81-503-3990001 / 01081-503-3990001 (0503-3990001 / 0-503-3990001) +81-503-3990002 / 01081-503-3990002 (0503-3990002 / 0-503-3990002) +81-503-3990003 / 01081-503-3990003 (0503-3990003 / 0-503-3990003) +81-503-3990004 / 01081-503-3990004 (0503-3990004 / 0-503-3990004) ...+81-503-xxxxxxx / 01081-503-xxxxxxx (0503-xxxxxxx / 0-503-xxxxxxx) ...+81-503-3999995 / 01081-503-3999995 (0503-3999995 / 0-503-3999995) +81-503-3999996 / 01081-503-3999996 (0503-3999996 / 0-503-3999996) +81-503-3999997 / 01081-503-3999997 (0503-3999997 / 0-503-3999997) +81-503-3999998 / 01081-503-3999998 (0503-3999998 / 0-503-3999998) +81-503-3999999 / 01081-503-3999999 (0503-3999999 / 0-503-3999999)