| Quek May Lian Jeslin | 4030 | Civil | 2006-04-18 | Fyfe Asia Pte Ltd |
| Quok Teck Soon | 4327 | Civil | 2009-09-17 | Core Tech Consultants Pte. Ltd. |
| Ramakrishnan Srinivasan Prakash | 4152 | Civil | 2007-02-23 | Land Transport Authority |
| Ramalingam Baskaran | 5373 | Electrical | 2021-01-21 | Aster Chemicals and Energy Pte Ltd |
| Ramesh Kumar Jaggi | 4940 | Chemical | 2017-09-19 | - |
| Ran Xujun | 4893 | Civil | 2017-06-15 | Worley Pte. Limited |
| Rao Yimin | 5148 | Electrical | 2018-09-20 | JTC Corporation |
| Raphael Choong Yeein Chern | 5365 | Civil | 2020-11-19 | LSW Consulting Engineers Pte. Ltd. |
| Ren Jiasheng | 5756 | Electrical | 2025-03-27 | SP PowerGrid Limited |
| Rengasamy Selvaraju | 3686 | Civil | 2002-01-15 | AECOM Singapore Pte. Ltd. |
| Richard Loh Ngee | 3377 | Civil | 1998-03-17 | SchistsNexus Consultants |
| Richard Phua Teck Meng | 4549 | Electrical | 2013-10-17 | - |
| Ricky Nagatie | 5552 | Civil | 2023-06-22 | Building and Construction Authority |
| Rita Wong Siong Ing | 5322 | Civil | 2020-04-16 | Building and Construction Authority |
| Rivan Rivaldy | 5581 | Mechanical | 2023-09-28 | Land Transport Authority |
| Roby Gunawan | 5388 | Civil | 2021-02-25 | Woh Hup (Private) Limited |
| Roger Martin Nicholas | 1012 | Mechanical | 1974-12-05 | Conpro Services Pte Ltd |
| Romanch Mittal | 5302 | Civil | 2020-01-16 | CKMbT International Pte. Ltd. |
| Rudi Lioe | 4515 | Civil | 2013-06-13 | Arup Singapore Private Limited |
| S Anand | 4330 | Civil | 2009-09-17 | Ministry Of Defence (MINDEF) |
| S Chandrasegaran s/o Sundararaju | 4346 | Civil | 2010-03-18 | Jacobs International Consultants Pte. Ltd. |
| S N Vasutavan | 1799 | Civil | 1982-08-16 | AI Vasu Chartered Engineers |
| S Nandha Kumar | 5705 | Electrical | 2024-09-26 | SP PowerGrid Limited |
| Sahabdeen Mohamed Mohideen | 4593 | Civil | 2014-04-17 | Infra Tech Professionals Pte. Ltd. |
| Sam Chang Loung | 4298 | Civil | 2009-03-19 | Fong Consult Pte. Ltd. |
| Sam Chee Yoong | 4550 | Electrical | 2013-10-17 | Ramboll Pte. Ltd. |
| Samuel Magnus Kilkenny-Brown | 5574 | Civil | 2023-07-27 | Amazon Asia-Pacific Holdings Private Limited |
| Sandoval Sherwin Joseph Camacho | 5845 | Civil | 2026-02-26 | KTP Consultants Pte Ltd |
| Sandy Kosnatha | 4614 | Civil | 2014-07-17 | Kimly Construction Private Limited |
| Sanjeet Singh Puarr | 5699 | Mechanical | 2024-09-26 | PUB, Singapore's National Water Agency |