Teams 
| Accomplishment | Date | |
|---|---|---|
| First Batter | Dave Collins | 4/6/77 |
| First Hit | Jose Baez | 4/6/77 |
| First Run | Dave Collins | 4/8/77 |
| First Win | 7-6, vs. California Angels, in the Kingdome | 4/8/77 |
| Winning Pitcher | Bill Laxton | 4/8/77 |
| First Save | John Montague | 4/8/77 |
| First RBI | Dan Meyer | 4/8/77 |
| First Game-winning Hit | Larry Milbourne | 4/8/77 |
| First Home Run | Juan Bernhardt off Frank Tanana (Cal) | 4/10/77 |
| First .500 Month | Record: 13-13 | August, 1978 |
| First Winning Season | Record: 83-79 | 1991 |
| First Division Championship | Record: 79-66 | 1995 |
