| Competition: | Segunda División B |
| Season: | 1986–87 |
| Winners: | Tenerife |
| Promoted: | Granada Lleida Real Burgos Tenerife |
| Relegated: | Mallorca Atlético |
| League Topscorer: | Manolo Muñoz (30 goals) |
| Best Goalkeeper: | Miguel Bastón (0.48 goals/match) |
| Biggest Home Win: | (5 October 1986) (31 May 1987) |
| Biggest Away Win: | (24 May 1987) |
| Highest Scoring: | (31 May 1987) |
| Matches: | 462 |
| Total Goals: | 1068 |
| Prevseason: | 1985–86 |
| Nextseason: | 1987–88 |
The 1986–87 Segunda División B season was the 10th since its establishment. The first matches of the season were played on 30 August 1986, and the season ended on 14 June 1987.
22 teams joined the league, including four relegated from the 1985–86 Segunda División and 6 promoted from the 1985–86 Tercera División.
| Goalscorers | Goals | Team |
|---|---|---|
 Manolo Muñoz | 30 | Granada |
| Jon Igoa | 20 | Real Sociedad B |
| Julio Suárez | 17 | Tenerife |
| 17 | Tenerife | |
| Mariano Mansilla | 16 | Córdoba |
| Goalkeeper | Goals | Matches | Average | Team | |
|---|---|---|---|---|---|
| Miguel Bastón | 20 | 42 | Real Burgos | ||
| Rafael Arumí | 20 | 28 | Lleida | ||
| Peio Aguirreoa | 33 | 42 | Tenerife | ||
| José Garmendia | 33 | 42 | Eibar | ||
| Ángel Lozano | 34 | 42 | Salamanca |