Iceland, Sweden, and Costa Rica have all succeeded in achieving 100% renewable energy.
Actually, Sweden generates 40% of its electricity from nuclear power plants, and has to import 3% of its electricity requirements. It does, though, produce 53% of its power from hydro electric generation.
The other two countries you mention derive the majority of their power (over 70%) from hydro electric generation. Additionally, both being located in volcanic areas, geothermal power stations also a contribute a significant amount (30% in the case of Iceland).
However, not all countries have many suitable hydroelectric sites. Even Australia's remarkable Snowy Mountains hydro electric scheme contributes barely 2% of the country's power requirements. Even fewer areas of the world have any geothermal potential.
Also, with hydroelectric generation, you are liable to encounter environmental issues of a different type. I come from a country that previously generated over 80% of its power requirements from hydroelectricity. That figure is now 54%, and falling - principally because of mass opposition from environmentalists, recreational fishermen, white water rafters and other pressure groups. In many quarters, hydro power has almost become a swear word!
When it comes to both hydroelectric and geothermal generation, the old saying "All that glitters is not gold" comes to mind.