Access to Sibu is via the small town of Tanjung Leman, about 130 km north of Johor Bahru and 72 km south of Mersing. There is no public transport to Tanjung Leman, so you need to sort out transfers with your resort from RM 80/person return, incl. boat or take a taxi around RM 180 from JB. If you want to cut back on your taxi fare, take a bus to Kota Tinggi first and continue from there. Some of the resorts operate shuttle buses directly from Singapore, with a total transfer time of about 3.5 hours.
There is no Ferry from Tanjung Leman to Sibu. All the resorts on the island arrange transport for visitors. The trip takes 30 mins and costs RM 70 return.