List of the top 20 organizations with the largest IP allocations in Japan
| Rank | Name | IPv4 addresses | IPv6 /64 networks | AS numbers | Prefixes |
|---|---|---|---|---|---|
| NTT Communications Corporation | 28,896,768 | 242 | 4 | 211 | |
| KDDI CORPORATION | 18,359,360 | 1.25 x 241 | 1 | 538 | |
| Research Organization of Information and Systems, National Institute of Informa | 8,974,910 | 233 | 1 | 625 | |
| 4 | Sony Network Communications Inc. | 4,296,192 | 1.22 x 237 | 1 | 349 |
| 5 | Internet Initiative Japan Inc. | 3,814,400 | 1.03 x 234 | 1 | 186 |
| 6 | BIGLOBE Inc. | 3,670,528 | 1.13 x 235 | 1 | 36 |
| 7 | JCOM Co., Ltd. | 3,665,920 | 1.5 x 233 | 5 | 306 |
| 8 | FUJITSU LIMITED | 2,754,816 | 232 | 1 | 48 |
| 9 | NTT PC Communications, Inc. | 2,336,512 | 1.56 x 233 | 1 | 170 |
| 10 | SoftBank Corp. | 2,010,880 | 232 | 2 | 175 |
| 11 | ARTERIA Networks Corporation | 1,736,960 | 1.5 x 236 | 1 | 162 |
| 12 | IDC Frontier Inc. | 1,442,560 | 234 | 2 | 191 |
| 13 | Asahi Net | 1,126,400 | 1.13 x 235 | 1 | 49 |
| 14 | Kintetsu Cable Network Co., Ltd. | 827,392 | 232 | 1 | 35 |
| 15 | QTnet,Inc. | 696,320 | 232 | 1 | 38 |
| 16 | ITEC HANKYU HANSHIN CO.,LTD. | 555,776 | 232 | 1 | 110 |
| 17 | TOYOTA DIGITAL CRUISE.INCORPORATED | 543,232 | 232 | 1 | 167 |
| 18 | STNet, Incorporated | 529,408 | 232 | 1 | 54 |
| 19 | NTT SmartConnect Corporation | 451,072 | 1.25 x 234 | 1 | 67 |
| 20 | SAKURA Internet Inc. | 364,032 | 232 | 1 | 51 |