| Rakuten, Inc. | Tokyo |
| Rams Design Co., Ltd | |
| Ranet Co., Ltd | Tokyo |
| Rapidus | |
| Rapyuta Robotics | Tokyo |
| Real Avatar Co., Ltd | Tokyo |
| Reality Accelerator | |
| Recosoft | Osaka |
| Recruit Payment Co., Ltd | Tokyo |
| RegCell Co., Ltd | Osaka |
| Rege Nephro Co., Ltd | |
| Rehatech Links, Inc. | |
| Rei-Frontier Co., Ltd | Tokyo |
| Reifycs, Inc. | Tokyo |
| Reinevo Corporation | |
| Reitaku University | |
| Reliable Technology Co., Ltd | Tokyo |
| Relipa Co., Ltd | |
| Remedy & Company Corporation | Tokyo |
| Remote Sensing Technology Center of Japan | |
| Renesas Electronics Corporation | Tokyo |
| Replies | Tokyo |
| Reprocell Co., Ltd | Kanagawa |
| ReqMed Co., Ltd | Tokyo |
| Research and Innovation Co., Ltd | Tokyo |
| Research Institute for Applied Sciences | |
| Research Institute of Innovative Technology for the Earth | |
| Research Organization for Information Science & Technology | Osaka |
| Researchmap | |
| Residence kit Co., Ltd | Tokyo |
| Resona Holdings, Inc. | |
| Resonac Holdings Corporation | Tokyo |
| Respo, Inc. | |
| Restore Vision, Inc. | |
| ReValue, Inc. | |
| RevComm Co., Ltd | Tokyo |
| RevolKa Co., Ltd | Tokyo |
| Rhelixa Co., Ltd | Tokyo |
| Rhipe Japan Co., Ltd | Tokyo |
| Ribomic Co., Ltd | Tokyo |
| Ricksoft Co., Ltd | Tokyo |
| Ricoh Company Ltd | Tokyo |
| Rigaku Corporation | Tokyo |
| Right Code Co., Ltd | Fukuoka |
| Rikei Corporation | Tokyo |
| RIKEN | |
| Riken Electric Wire Co., Ltd | Tokyo |
| Rikkyo University | |
| RimArts, Inc. | Chiba |
| Ringo Mac User Group | Tokyo |