KSL City Mall is one of the shopping centres in Johor Bahru, Malaysia, that is closest to Singapore and is thus a popular shopping destination for day-trippers from Singapore. It also has a Tesco supermarket (now renamed to Lotus's) where Singapore residents will go for groceries and cheap buys.
If you are not sure how to go over the Causeway from Singapore via Woodlands Checkpoint to JB Sentral, read this post: Bus Guide: Singapore to JB Sentral or City Square in Johor Bahru
A. From JB Sentral to KSL City Mall
If you are going to KSL City Mall from JB CIQ / JB Sentral, walk to the bus terminal below JB Sentral — go down the escalator between JB CIQ and JB Sentral. Then, walk towards the end of the bus terminal for Bus Bay (Hentian Bas) 1 or 2. Look for the dedicated myBAS F100 shuttle service (used to be called "S1"), operated by Causeway Link.
myBAS F100 traversed directly between JB Sentral and KSL City Mall, with additional stops at Plaza Pelangi and Holiday Plaza along its route. The shuttle service starts as early as 8:15am and will stop at the main entrance of KSL City Mall. The bus fare is RM1.50 one-way.
To return to JB Sentral, board at the same place where you drop off. The fare is RM1.50 and the last service is at 11pm.
Do note that, on Monday nights, there will be a night market (or pasar malam) along the road in front of KSL City Mall, near the main entrance. The road will be closed to vehicles. If you are there on a Monday night and taking the shuttle service to JB Sentral, board the bus at the basement exit instead of at the main entrance after 3pm. There will be no signpost to identify where to queue for the shuttle bus, so look or ask around for the queue or start a new one — only if there are none.
B. From Larkin Sentral to KSL City Mall
There is no direct bus services between Larkin Sentral and KSL City Mall even though they are only about 5Km apart. Use Grab service if you have mobile data.
If really want to use bus services from Larkin Sentral, take myBAS T13 at Platform A and alight at the bus stop for Taman Sri Tebrau or opposite Crystal Crown Hotel. Cross the road and walk about 600 metres to KSL City Mall.
Alternatively, use bus services with one stop-over at JB Sentral. At Larkin Sentral, go to Platform A and board myBAS T10 (or any bus with a "JB Sentral" sign on its windscreen), then change to myBAS F100 at JB Sentral to KSL City Mall. It will probably take more than 30 minutes excluding waiting time at both bus terminals.