I also found this on a relatively recent Lonely Planet forum:
DANGRIGA / PLACENCIA, BELIZE TO PUERTO CORTES, HONDURAS
Nesymein Neydy departs from Dangriga on Thursday mornings 8:30am.
Arrives at Placencia Texaco Gas Station dock Thursday a.m.
Departs Placencia at 11:00 a.m.
Arrives at Puerto Cotes about 1:30pm.
Return trip: Departs Puerto Cortes on Tuesdays at 11:00am.
Cost: US$50.00 each way
(as at March 2007)
PLACENCIA, BELIZE TO PUERTO CORTES, HONDURAS
D-Express departs from Placencia Tourism Center, next to the Shell Gas Station on Fridays at 9:30 a.m. (check in at 9:00)
Arrive Big Creek at 10:00 a.m. (for Customs).
Depart Big Creek at 11:00 a.m.
Arrive Puerto Cortes, Honduras at 2:00 p.m.
Return trip: Depart Puerto Cortes, Honduras on Mondays at 10:00 a.m.
Arrive Big Creek at 12:00 noon.
Depart Big Creek at 1:30 p.m.
Arrive Placencia at 2 p.m.
US$50.00 each way. Tickets available at the Placencia Tourism Center. Tel: 202-4506 or 523-4045
(as at March 2007)
This could have changed, but it looks pretty convincing. As a back-up:http://www.placencia.com/Informative%20_%2...elize.htm#WATER
THE EXPRESS WATER TAXI: (Tickets available at the Placencia Tourism Center)
Departs Placencia Fridays - 9:30 a.m. Arrives Big Creek 10 a.m. Departs - 11:00 a.m.
Arrives Puerto Cortez, Honduras, 2 p.m. at Laguna.
Departs Puerto Cortez , Honduras Mondays - 10 a.m. Arrives Big Creek 12 noon. Departs - 1:30 p.m.
Arrives Placencia 2 p.m.
Tel: 202-4506 or 523-4045.
If you are not yet convinced, try this - Lan Sluder knows everything there is to know about Belize, and how to get there.
Free Answers to Any Question About Belize! Get any question about Belize answered by an expert ... free. Lan "The-Belize-Answer-Man" Sluder is editor of Belize First Magazine and the author of several books on Belize, including San Pedro Cool, Belize First Guide to Mainland Belize, Adapter Kit: Belize and Living Abroad in Belize. His new guidebook, Fodor's Belize 2008, is now in bookstores worldwide. If he can't answer your question, he'll find someone who can.
Got a question? Just email it to firstname.lastname@example.org. Get an answer within 24 hours (usually).