| OMNIDC JAKARTA | PT Omni Data Center Indonesia | Jakarta | Indonesia | 20 | 1 |
| Omnis Network Phoenix | Quantum Names, LLC | Tempe | United States | 4 | 0 |
| ONE (iAdvantage Hong Kong) | iAdvantage Hong Kong | Hong Kong | Hong Kong SAR China | 1 | 0 |
| One Albania | One Albania | Tirana | Albania | 0 | 0 |
| OneHostPower Datacenter | Ukrnames LLC | Kharkiv | Ukraine | 0 | 0 |
| OneNet OSU Tulsa | Oklahoma State Regents for Higher Education | Tulsa | United States | 2 | 0 |
| ONI Telecom Lisbon Matinha | OniTelecom | Lisbon | Portugal | 7 | 1 |
| ONIX Data Centre Accra | ONIX Data Centres (Ghana) Limited | Accra | Ghana | 9 | 2 |
| ONIX Senegal | ONIX Senegal | Dakar | Senegal | 3 | 1 |
| Online Solution | Online Solution 360 GmbH | Gruenwald | Germany | 0 | 0 |
| Online.pt LIS1 Datacenter | Online.pt | Barreiro | Portugal | 0 | 0 |
| OODOO Communications | OODOO Communications | Chennai | India | 1 | 0 |
| Opciones - Concepción | Opciones | Concepción | Chile | 0 | 1 |
| Opciones - Puerto Montt | Opciones | Puerto Montt | Chile | 0 | 0 |
| OPCORE - DC2 / PAR2 | OPCORE | Vitry-sur-Seine | France | 46 | 4 |
| OPCORE - DC3 / PAR3 | OPCORE | Vitry-sur-Seine | France | 26 | 4 |
| OPCORE - DC4 / PAR4 | OPCORE | Paris | France | 1 | 0 |
| OPCORE - DC5 / PAR5 | OPCORE | Saint-Ouen-l'Aumône | France | 6 | 0 |
| Open DC D8-1 - Bukit Kayu Hitam | OPEN DC SDN BHD | Bukit Kayu Hitam | Malaysia | 0 | 0 |
| Open DC JB1 - Menara MSC Cyberport | OPEN DC SDN BHD | Johor Bahru | Malaysia | 15 | 2 |
| Open DC JB2 - Menara Ansar | OPEN DC SDN BHD | Johor Bahru | Malaysia | 5 | 2 |
| Open DC PE1 - Suntech Penang Cybercity | OPEN DC SDN BHD | Penang | Malaysia | 5 | 3 |
| Open Hub Med | Open Hub Med Scarl | Carini | Italy | 25 | 2 |
| Open IT Group | OPEN IT SOLUTIONS EIRELI | Cabreúva | Brazil | 0 | 0 |
| OpenColo | Energy Group Networks LLC | Santa Clara | United States | 25 | 3 |
| Openface DC2 | Openface Internet Inc., Colocation Operations Div. | Montreal | Canada | 1 | 0 |
| OpenX - Verbo Divino | Open X Tecnologia Ltda | São Paulo | Brazil | 5 | 0 |
| OPTAGE – OC1（Sonezaki DC） | OPTAGE Inc. | Osaka | Japan | 6 | 3 |
| OPTAGE – Shinsaibashi DC | OPTAGE Inc. | Osaka | Japan | 0 | 0 |
| OPTAGE – Umedakita DC | OPTAGE Inc. | Osaka | Japan | 1 | 0 |
| Optic Fusion - Perkins Building | Optic Fusion | Tacoma | United States | 2 | 0 |
| Optic Fusion - Westin Building 2505 | Optic Fusion | Seattle | United States | 1 | 0 |
| OPTICNET Ploiesti | OPTICNET - SERV S.R.L. | Ploiesti | Romania | 1 | 0 |
| Opticom Quito DC01 | OptiCom | Quito | Ecuador | 0 | 0 |
| Optimus Technologies Dhaka | Optimus Technologies | Dhaka | Bangladesh | 1 | 0 |
| Options IT - Park Royal Datacenter (PRDC) | Options Technology Ltd. | London | United Kingdom | 4 | 0 |
| Optizon Krasnoyarsk | Optizon Ltd. | Krasnoyarsk | Russia | 3 | 0 |
| Optus Ultimo | Singtel Optus | Sydney | Australia | 1 | 0 |
| Opus Interactive Dallas (DTX01) | Opus Interactive, Inc. | Dallas | United States | 0 | 0 |
| Opus Interactive Hillsboro (HIO01) | Opus Interactive, Inc. | Hillsboro | United States | 4 | 1 |
| Opus Interactive Portland (PDX01) | Opus Interactive, Inc. | Portland | United States | 0 | 0 |
| Opus Interactive Silicon Valley (SJC01) | Opus Interactive, Inc. | San Jose | United States | 0 | 0 |
| Orange / Chartres | Orange S.A. | Amilly | France | 1 | 0 |
| Orange / Val de Rueil | Orange / Val de Rueil | Val de Reuil | France | 4 | 0 |
| Orange Business - La Fabrique [Grenoble] | Orange Business - La Fabrique | Grenoble | France | 14 | 1 |
| Orange Business Services Rostov-na-Donu | Orange Business Services | Rostov-na-Donu | Russia | 3 | 0 |
| Orange Cameroun Datacenter Makepe-Douala | Orange Cameroun SA | Douala | Cameroon | 1 | 0 |
| Orange Polska / Warsaw św. Barbary 10 | Orange Polska Spolka Akcyjna | Warsaw | Poland | 19 | 0 |
| Orange Polska // Białystok | Orange Polska Spolka Akcyjna | Białystok | Poland | 8 | 1 |
| Orange Polska // Bydgoszcz | Orange Polska Spolka Akcyjna | Bydgoszcz | Poland | 7 | 1 |