| Jamie Tsan Li Ling | 5753 | Electrical | 2025-03-27 | Simec Technology Pte Ltd |
| Jayasankar Rathina Sankar | 5225 | Civil | 2019-06-20 | IC Singapore Pte. Ltd. |
| Jee Yi Yng | 4123 | Civil | 2007-02-23 | AECOM Singapore Pte. Ltd. |
| Jeevanath Surendranath | 5197 | Civil | 2019-01-17 | VSJ Consulting Engineers |
| Jefferson Lim Chin Siong | 5545 | Mechanical | 2023-05-18 | AECOM Singapore Pte. Ltd. |
| Jerald Antony Palatty | 5814 | Mechanical | 2025-10-23 | CASY Engineering Consultancy Pte. Ltd. |
| Jeremy Tan | 5800 | Civil | 2025-10-23 | China Communications Construction Company Limited |
| Jessica Strauch-Yip Min Yi | 5498 | Mechanical | 2023-01-26 | Leong CW & Associates Pte. Ltd. |
| Jessie Chai Xia Hui | 5566 | Civil | 2023-06-22 | Beca Carter Hollings & Ferner (S.E.Asia) Pte Ltd |
| Jeyarajah Jeyananthanan | 5109 | Civil | 2018-07-19 | Meinhardt Infrastructure Pte. Ltd. |
| Jeyarajan Selvarajah | 5189 | Civil | 2018-12-14 | WSP Consultancy Pte. Ltd. |
| Ji Jiaming | 5084 | Civil | 2018-06-21 | Arup Singapore Pte Ltd |
| Jia Junduo | 5863 | Electrical | 2026-03-26 | Land Transport Authority (LTA) |
| Jiang Chao | 5841 | Civil | 2026-01-22 | Surbana Jurong Consultants Pte. Ltd. |
| Jiang Yijie | 5616 | Civil | 2024-01-25 | AECOM Singapore Pte. Ltd. |
| Jiao Lei | 4909 | Chemical | 2017-07-18 | Worley Pte. Limited |
| Jiao Runxing | 5886 | Civil | 2026-04-23 | Building And Construction Authority (BCA) |
| Jim Tuck Seng | 3345 | Electrical | 1997-08-19 | - |
| Jimmy | 5254 | Mechanical | 2019-09-19 | Rankine & Hill (Singapore) Pte. Ltd. |
| Jin Guosheng | 4468 | Electrical | 2012-09-20 | Maintech Engineering & Supplies Pte Ltd |
| Joan Lim Aiy Nak | 5709 | Civil | 2024-09-26 | - |
| Joel Yeo Wei Wen | 5473 | Electrical | 2022-08-25 | T Yeo Engineers |
| John Baptist Tan Kar Him | 4008 | Mechanical | 2005-09-20 | - |
| Johnson Nurjan Boewono @Ng Cheng Huat | 4175 | Electrical | 2007-04-19 | Surbana Jurong Consultants Pte. Ltd. |
| Jong Tien Iou | 5796 | Civil | 2025-09-05 | Land Transport Authority |
| Joseph s/o G K Samy | 4508 | Electrical | 2013-04-18 | SP PowerGrid Limited |
| Justin Tai Wen Xiong | 5313 | Mechanical | 2020-02-20 | Building and Construction Authority |
| Kalandar Naina Mohamed Mohamed Jawith | 4964 | Electrical | 2017-10-23 | Rankine & Hill (Singapore) Pte. Ltd. |
| Kam Kwee Eng | 2496 | Civil | 1989-07-19 | SP PowerGrid Limited |
| Kam Mun Wai | 3479 | Civil | 1999-06-15 | Meinhardt (Singapore) Pte Ltd |