Taking the bus from Johor Bahru, Malaysia to Singapore is easy once you know what to do.
First go to the Custom and Immigration Quarantine Complex (CIQ) in downtown Johor Bahru right near the causeway to Singapore. Walk through the complex to leave Malaysia (you need your passport, obviously). Once you clear Malaysian passport control you follow the signs to Singapore/Woodlands for the bus (on your left after you leave the passport area). You go downstairs and catch your bus. You pay for the bus, on the bus.
Lines for bus to Singapore at Malaysia CIQ. On the signs (and the ground) they list what buses the queues are for.
There are various options but the 3 most common are:
Queen Street (this gets you to downtown Singapore). You can take the CW2 (direct) of the 160 (many stops – so really you probably don’t want to chose this unless you want to get off before queen street). The Queen street stop lets you off right near Little India. Cost is under RM 4 (update 2014 – with increases in tolls the busses hiked fares by under 1 RM, they are a much better value now, since car and taxi tolls increases so much).
MRT – if you want to go to the Singapore MRT you can take the 170 or CW1 to Kranji station. Woodlands is the closest station but there isn’t a bus to there (that I know of). Cost is under RM 3 (after 2014 increase).
Airport – the airport bus takes you directly to the Changi Airport in Singapore and costs RM 7 (from Singapore to JB it costs SGD 7 – I am not sure of the prices after the 2014 increase). The bus is a small bus (seats about 20 maximum) – asking people where it is, will be the easiest way to find it. This bus only runs once an hour. This bus works great but you should be aware if you get stuck in customs trying to get into Singapore it is possible the bus will leave without you. If that happens catch the 170 to Kranji and take the MRT to the airport. I think the bus will wait 20 minutes for people to clear customs (and if several of you are not back yet the bus may wait, but missing it is something to consider).
Kranji MRT in Singapore. There is a bakery right where the bus lets you off. To catch the bus back to Customs you have to cross over the road so you are on the opposite side from the MRT.
The busses will take you across the causeway to Singapore and then you will disembark (with any luggage and belongings) and go through Singapore customs and then go back downstairs and catch your bus. The CW1, CW2, 170 and 160 run frequently during the day and evening (every few minutes to every 15 minutes for some).
Overall it is an easy process and doesn’t take too long. But at rush hours (especially Friday night or on holidays) it can get very busy and backed up. I hear the morning rush from JB into Singapore is pretty bad, but I have gone a bit later (9:30 AM) when I have gone, and it has been fine (most of the time).
The prices are from Singapore to JB are the same number but in SGD which means about 2.5 times as much money. So, for example, from Queen Street to JB is $3.30 (versus 3.30 RM).
Related: Bus to Jusco in Permas Jaya – Plaza Pelangi in Johor Bahru Town – resources for living in Johor Bahru