The Swans put on their worst display of the season to gift all three points to relegation-threatened Carlisle in what is likely to be Alan Curtis' last match as caretaker-manager.
They took the lead in the 16th minute when Paul Connor threaded a header through the legs of visiting keeper Peter Keen but ten minutes later the Cumbrians were on level terms when Craig Farrell was brought down in the box needlessly by Swans central defender Alan Tate.
Farrell picked himself up and slotted the spot kick neatly into the corner of the net.
Carlisle then took control of the game and it was no surprise when they went ahead on the hour when Peter Duffield drove in a cross from Andy Preece with no Swans defenders anywhere near him.
Despite bringing on Kevin Nugent and James Thomas the Carlisle defence held firm to the delight of player-boss Paul Simpson.
"We worked hard in training during the week at keeping a tight back four as we knew Lee Trundle would be a threat," Simpson said. "To be applauded off the field by the Swansea supporters was especially pleasing but we still have a long way to go and we have to keep our performance levels up through and into our next match.
"Everyone must give 100% and today we have all worked hard and reaped the reward and if we play like that until the end of the season we will win more than we lose." With a new managerial appointment being announced on Monday with Kenny Jackett the present QPR number two as the favourite, Alan Curtis came to the end of his short spell as caretaker.
"It was an awful game today. They were fighting for their lives just as we were last year and they got stronger and stronger as the game went on.
"I am disappointed that we haven't worked hard enough in the last couple of games while I have been in charge. The players will have to put in far better performances than that to the end of the season but the player base here is strong and the new manager may only have to tweak things about a little.
"We are definitely going to be short of the play-offs so now is the opportunity to start planning for next season."