Travelling from Panama to Colombia?

Norbert is right as far as he goes and the sailing boat route in clearly the more comfortable. There used to be a ferry from Barranquilla or Cartegena but now the route is more complicated. You can go to Colon to take a boat to Puerto Oboado in Panama and from there you can take a water taxi to the nearest Colombian town. From there you can take a regularly scheduled boat to a place where you can take a bus to anywhere in Colombia.