Ian Holloway's men went into their final fixture knowing victory would guarantee a top-six finish, but Swansea's failure to beat Doncaster ensured a point was more than enough for the Seasiders.
Nicky Maynard gave mid-table City a surprise first-half lead with a wonderful opportunist strike. But Brett Ormerod levelled nine minutes after the break to earn the hosts a share of the spoils.
Blackpool are now just three games away from securing promotion to the top flight for the first time in 40 years.
They will take on Nottingham Forest over two legs, with the winner meeting Cardiff or Leicester at Wembley on May 22.
Blackpool almost made the perfect start as Charlie Adam drilled a shot narrowly wide of Dean Gerken's right-hand post in the third minute.
City offered little as an attacking force early on, but they took the lead in the 16th minute courtesy of a moment of magic from top scorer Maynard. A long ball was flicked on to the former Crewe striker and he spotted Blackpool goalkeeper Matt Gilks off his line before finding the net with a dipping half-volley from 30 yards.
The Seasiders looked for an immediate response and they almost levelled in the 23rd minute as David Vaughan's inswinging corner was clawed off the line by Gerken. Campbell twice shot wide from promising positions and Seamus Coleman also failed to hit the target as City held on to their lead with relative comfort going into the interval.
The hosts drew level in the 54th minute as Ormerod powered home a header from Adam's curling free-kick. And Gerken made a fine stop to deny Ormerod a second goal in the 59th minute after the striker had beaten the offside trap.
Blackpool remained in the ascendancy and went agonisingly close to taking the lead with 18 minutes to go as Dobbie's thunderous 25-yarder was tipped over by Gerken. But they needed Gilks to be alert to keep out a late strike from Jamal Campbell-Ryce.
Source: PA
Source: PA