To get to Semakau Island you have to take a boat ride from Marina South Pier.
The journey takes about 45 minutes to 1 hour.
You have to book the trip from either one of these clubs:
1. Raffles Museum of Biodiversity Research - Intertidal Walk
2. The Nature Society - Birdwatching
3. Sport Fishing Association - Sport Fishing
Currently, entry to Pulau Semakau is restricted and there's only 3 groups with direct access there so you'll need to contact them before making a trip there. They are:
1)Nature Society organises birdwatching trips for members only at $25.
2)Sport Fishing Association organises angling tours for its members at $30 and members of the public at $40.
3)Raffles Museum of Biodiversity Research(NUS) organises inter-tidal walks for Public at $52.50 per person.
All of these groups will ask you to fill up at least 2 forms before going and they are
1)Indemnity forms ( they're not responsible if you decide to jump off the boat or get attacked by a crazed flock of eagles)
2)Entry permit from National Environment Agency
Other than all these, just note that these trips are usually made in the Gordforsaken hours of the morning. The groups usually meet at the West Coast Pier (near Republic of Singapore Yacht Club) at about 6-7am to take a chartered boat to the island. There is an immigration area there so you'll need to bring your i/c or passport (even if you're a local) to go to Pulau Semakau.