The 1988–89 I-Divisioona season was the 15th season of the I-Divisioona, the second level of Finnish ice hockey. 12 teams participated in the league, and JoKP Joensuu won the championship. JoKP Joensuu and Jokerit Helsinki qualified for the promotion/relegation round of the SM-liiga.
| Club | GP | W | T | L | GF–GA | Pts | ||
|---|---|---|---|---|---|---|---|---|
| 1. | 44 | 32 | 4 | 8 | 250:137 | 68 | ||
| 2. | 44 | 30 | 4 | 10 | 278:173 | 64 | ||
| 3. | 44 | 28 | 0 | 16 | 228:177 | 56 | ||
| 4. | 44 | 25 | 2 | 17 | 215:175 | 52 | ||
| 5. | 44 | 26 | 0 | 18 | 277:241 | 52 | ||
| 6. | 44 | 22 | 1 | 21 | 220:216 | 45 | ||
| 7. | 44 | 21 | 2 | 21 | 216:250 | 44 | ||
| 8. | 44 | 19 | 4 | 21 | 214:211 | 42 | ||
| 9. | 44 | 17 | 3 | 24 | 250:228 | 37 | ||
| 10. | 44 | 17 | 2 | 25 | 204:233 | 36 | ||
| 11. | 44 | 8 | 1 | 35 | 156:325 | 17 | ||
| 12. | 44 | 6 | 3 | 35 | 140:282 | 15 |