There are a multitude of volunteer programs available in Education, Health, Environment and Community services around the world.

Organizations like Red Cross and UN Volunteers also enroll volunteers, and some of them can be considered among the biggest by size.

If you consider organization size, some of them can be considered one of the biggest. But the answer is very subjective and relies on what aspect of "big" we are looking for — organization size, years served, countries served, or something else.

Volunteer FDIP, Worldpackers, Workaway, and IVHQ are some of the organizations that offer reputable volunteer programs.

Goabroad.com has been listing different volunteer opportunities for many years.

However, if you want to connect directly with volunteer providers, websites like volunteerfdip.org and worldpackers.com are also among the best.

To know if an organization is legitimate, check their official registration, presence in trusted directories, and reviews and ratings from previous volunteers.

Volunteer FDIP offers similar programs with better pricing and options in many Asian destinations.

However, the answer depends on which country and project you are comparing.

Volunteer FDIP offers many destinations and programs similar to those offered by IVHQ.

Volunteer FDIP has highly rated and reviewed volunteer abroad programs, making it one of the most reputable.