Coming from USA or Canada, you can easily fly into Belize City via Dallas, Miami, Houston, Atlanta and Charlotte. From there you have the choice between an airplane (12 flights a day) or a bus (4 departures a day) into Placencia.
From Europe you have the choice over America, usually with 2 to 3 connecting flights resulting in a 30 hours plus journey, which is most of the time more expensive than flying into Cancun, Mexico with a charter company. From Cancun you can catch a flight to Belize City for 199 US$, allowing you to arrive the same day in Belize City. The next morning you can fly to Placencia for some 75 US$.
From Cancun you can also take a bus through Chetumal into Belize City (50 US$) and further onto Placencia by bus or by plane. We advise you to stay over for the night in Playa del Carmen (a charming place 50km south of Cancun airport with regular bus service to and from) before undertaking the journey to Belize City by road.
If you are 2 or more, it is usually quite economical to rent a car in Cancun (some 40 to 50$ a day) for which you get additional comfort and freedom and you save on excursions. Make sure you use a car rental company (e.g. Europcar) which is prepared to give you the authorization letter to cross the border with Belize. A car high on wheels is the better choice, keeping in mind you will have to use a dirt road to get to Placencia, but a normal sedan will get you there as well when you drive carefully on the dirt road.
Playa del Carmen to Placencia is 700km on well maintained roads except for the last 25mls/35km, which is a dirt road. It can be done in some 10 hours with stops of half an hour each 200km and a probable 1 hour delay at the border to comply with the administrative procedures; you have to get complementary third party liability insurance for Belize which is not expensive, you have to have your car sprayed against mad cow disease, you have passport and customs control and you have to register your car.
Those who want to visit some impressive Maya sites en route can elect to travel 2 days towards Placencia. A worthwhile stop is Tulum in Mexico, which is some 50 km south of Playa del Carmen. Leaving there at the latest at 12 noon will allow you to cross the border with Belize before dark and have a stop at Corozal, 10 km south of the border. There's a comfortable hotel Tony's Inn along the lake. The next morning you can call onto the Lamanai temple off the road to Belize City not far from Orange Walk.
Approaching Belize City, you should turn right in the direction of Burrel Boom right after an army checkpoint. Stay on that road till the next roundabout and head for Belmopan; this way you avoid the traffic of Belize City. Go all the way to Belmopan and ignore the Placencia sign post on the western highway; it is a shorter route but includes 40mls/60km dirt road.
Once in Belmopan, Belize's capital, you head to the south east over the enchanting Hummingbird highway through the Maya Mountains. Before entering Dangriga, turn right onto the Southern highway and drive another 50km till the junction with the dirt road into Placencia. On this road keep right at all road junctions. Pass the village of Seine Bight and proceed till you arrive at the Placencia airport. Michelo's flats are at 1 km from the airport on the main street into the village on the left hand side just after the Atlantic Bank.