Leading scorer Lee Trundle opened the scoring for the home side in the 55th minute with a great close-range strike.
The Shrimpers bounced straight back and Wayne Gray took advantage of slack marking by the home defence to level the scores with a snap-shot into the corner.
Swansea were forced to make one change to their starting line-up with Brad Maylett in for the injured Adrian Forbes while Southend kept young scoring sensation Freddy Eastwood on the bench.
Defences were on top in the early stages and neither keeper was called into action as the visitors' midfield threatened to take control.
A move started by Leon Britton on the half-hour was almost finished off by Trundle but Darryl Flahavan in the Shrimpers goal got down to block at the foot of his post.
Southend hit back by forcing a couple of corners but the home defence held firm.
On the stroke of half-time, Britton forced a rare opening but his first-time shot went straight to the keeper.
The Swans had a chance to break the deadlock six minutes after the break but after Paul Connor and Trundle had seen their attempts blocked, Sam Ricketts lifted his shot high over the bar.
Swansea then took the lead after forcing the Southend defence to back-pedal with a sustained attack during which Connor struck the woodwork with a close-range header.
When the ball was cleared it was quickly returned to the danger area were Trundle was waiting and he turned to smash a shot into the roof of the net for his 18th goal of the season.
Just as it seemed that Swansea were heading for the top of the table the Shrimpers equalised out of the blue. A long ball down the middle was chased by Gray and he beat Gary Monk to the ball before firing into the corner of the net.
Both sides had chances to steal all the points with Swansea going closest when Trundle struck the post with the final kick of the match but a draw was a fair result and keeps both sides in the promotion race.