Both sides will take their place alongside another 60 European outfits to see who they must face to progress through to the group stage which begins in September.
The good news for both sets of supporters is that Spurs and the Swans have been seeded, leaving them with a selection of weaker teams that they could be drawn with in today's draw.
Below, Sports Mole tells you who your club could be paired with later on Friday.
Tottenham Hotspur are now experienced European campaigners, and they made the quarter-finals of this competition last season.
Heading into the draw, the White Hart Lane outfit hold one of the highest European coefficients and they shouldn't experience too many problems, whomever they face in the playoffs.
Czech Republic side Slovan Liberec are arguably their toughest possible opponents, having won their domestic league title in 2012.
They finished in third position last year, but they haven't made the main stage of a European competition since 2006, earning four points from their four matches in the UEFA Cup.
FC Thun are another of Tottenham's potential opponents, but their lack of pedigree is exposed after losing 5-1 on aggregate to Stoke City at the same stage of this competition two years ago.
Georgian outfit Dinamo Tbilisi won the UEFA Cup Winners Cup in 1981, but 32 years on, they are a shadow of that side, and have not made the main stages in Europe since 2006.
Other possible opposition for Spurs are Austria's FC Pasching, Estonia's JK Nomme Kalju and Romania's FC Astra.
Swansea City are playing in European competition for the first time in over 20 years, and they will be confident of an extended stay this time around.
They impressed in dispatching of Malmo by a 4-0 scoreline last week, before completing the job in Sweden last night.
The Swans have been handed a favourable group of potential opponents, but one team could pose them a few problems.
Greek outfit Atromitos are, by far, the most testing fixture that Swansea could face, with their quality highlighted by a narrow aggregate defeat to Newcastle United last season.
They also finished in third position in the Greece Superleague last season, and the Athens-based side are one to avoid.
The remainder of their selection is made up of weak opposition, with Cyprus club Apollon Limassol the only name that Swans fans may recognise.
They could also face Kazakhstan's FC Aktobe, Iceland's FH Hafnarfjordur or Romania's FC Petrolul Ploiesti.