Japan
IP address space, AS numbers and the largest networks registered in Japan, based on the delegation records of the regional internet registries.
IPv4 addresses
186.9M
4,774 blocks
IPv6 allocations
786
AS numbers
1,304
Routed AS numbers
616
Largest networks in Japan
By announced prefixes| AS | Name | IPv4 prefixes | IPv6 prefixes |
|---|---|---|---|
| AS9605 | docomo NTT DOCOMO, INC. | 861 | 334 |
| AS2907 | SINET-AS Research Organization of Information and Systems, National Institut... | 605 | 2 |
| AS2516 | KDDI KDDI CORPORATION | 562 | 9 |
| AS17676 | GIGAINFRA SoftBank Corp. | 482 | 3 |
| AS2514 | InfoSphere NTT PC Communications, Inc. | 468 | 4 |
| AS10013 | FBDC FreeBit Co.,Ltd. | 407 | 3 |
| AS4694 | IDCF IDC Frontier Inc. | 330 | 5 |
| AS2497 | IIJ Internet Initiative Japan Inc. | 242 | 11 |
| AS7687 | D-CRUISENET TOYOTA SYSTEMS CORPORATION | 211 | 0 |
| AS4713 | OCN NTT DOCOMO BUSINESS,Inc. | 181 | 6 |
| AS58647 | KAGAWAU-AS Kagawa University | 185 | 0 |
| AS2519 | VECTANT ARTERIA Networks Corporation | 182 | 2 |
| AS58791 | GMO-I-R2 GMO Internet, Inc. | 181 | 2 |
| AS3258 | XTOM-JAPAN xTom Japan Corporation | 134 | 26 |
| AS7524 | HANSHIN ITEC HANKYU HANSHIN CO.,LTD. | 132 | 1 |
| AS55374 | FJcloud-East FUJITSU LIMITED | 120 | 4 |
| AS59109 | HITCLOUD Hitachi,Ltd., Managed & Platform Services Business Division | 111 | 0 |
| AS18283 | CCV Chupicom Inc. | 97 | 1 |
| AS2527 | So-net Sony Network Communications Inc. | 74 | 2 |
| AS151386 | NCJ-NET NHN Cloud Japan Corporation | 73 | 0 |
| AS59107 | HTV-NET Hachinohe Cable Television Co. | 69 | 0 |
| AS17511 | OPTAGE OPTAGE Inc. | 66 | 2 |
| AS17514 | AICS Otsuka Corp. | 67 | 1 |
| AS4785 | XTOM-AS-JP xTom | 46 | 20 |
| AS18126 | CTCX Chubu Telecommunications Company, Inc. | 63 | 2 |
| AS4685 | ASAHI-NET Asahi Net | 62 | 2 |
| AS7671 | MCNET NTT SmartConnect Corporation | 61 | 2 |
| AS131965 | XSERVER Xserver Inc. | 60 | 2 |
| AS2510 | INFOWEB FUJITSU LIMITED | 60 | 1 |
| AS134351 | LEASEWEB-AS-AP Leaseweb Japan K.K. | 53 | 2 |
Delegations by registry: APNIC 5,481, RIPE 40, ARIN 39. Updated 2026-10-05.