It's possible to circumnavigate the globe by hitchhiking. This article gives some ideas how.
Different people have different goals for worldwide hitchhiking. Some questions to consider:
- Are you planning to visit all 6 populated continents? Or just to stay moving in a roughly easterly or westerly direction until you return to where you started?
- What are your time constraints? Can you take a year, or two, or three, to complete the trip?
- How far are you willing to go on paid transportation?
- Do you plan to walk or bike part of the way?
- Will you pay for food and lodging?
Hitchwiki is by far the best source of information for hitchhikers. Read up about the different country articles and use the city articles to get out of bigger cities.
Crossing the Pacific or Atlantic Oceans present some difficulty. This can be overcome with grit and determination. See Round the world overland and Hitchhiking boats. Hundreds of sailing boats cross the oceans every year (although quite few do all the Pacific). Waiting in busy ports like Grenada, Madeira or Panama can help. Talk to boat owners, be friendly, helpful, and approachable. Something may turn up. The Internet is also a useful resource, there are many websites that match crew with short-handed skippers. They might just be going the right way.