| American Amateur Baseball Congress: Coordinates play among US leagues in seven age brackets, from sub-teens through adults. Includes rules, tournament dates, and list of regions and age divisions. |
| National Adult Baseball Association: NABA amateur baseball organization information, including tournament results, events and how to join. |
| Over 50 Baseball: Promoting an affordable week-long fantasy-camp type fun tournament in Las Vegas each October. Also promoting the establishment of local leagues nationwide. |
| Roy Hobbs Adult Baseball: Amateur baseball organization for adults over the age of 28. |
| Team One Baseball: Scouts baseball's high school, college and minor league players and compiles information on the annual Baseball Draft. |
| Ventura National Adult Baseball Association: League guide to teams for people age 18 and older. Features information on team play, current standings, newsletter, and game schedules for amateur organization. |
| Vintage Base Ball Association: Listing of rules, tournaments, members and contact information. |
Classical
