The cheapest approach to reach Ibo is arriving toTandanhangue (camping there) and then wait for the correct tide to catch dhow-sheet (40 meticais) to the island. But to reach Tandanhangue need lots of patience, because the transportation is very limited. You can reach Quissanga and then walking.
To enjoy the walk through the ocean between these two islands (Ibo and Quirimba), check the tides and good times. It is best to hire a fisherman to take you back and walk in his old wooden sailboat, or in reverse.