Operated by SBST
| Direction | First bus (wkday) | Last bus | AM peak | AM off-peak | PM peak | PM off-peak |
|---|---|---|---|---|---|---|
| Blk 991A → Prince Edward Rd Stn Exit 2 | 07:26 | 08:00 | 11–12 min | — | — | — |
| Aft Enggor St → Opp Blk 991A | 18:05 | 18:25 | — | — | 20 min | — |
First/last bus are at the origin stop, weekdays. Frequencies are LTA's scheduled ranges in minutes.