The semi-finals are the penultimate round of the Champions League, contested by the four clubs that survived the quarter-finals. Two two-legged ties are played in late April and early May, with the first legs roughly seven days before the second legs. Pairings, again, are pre-determined from the start of the knockout phase — quarter-final winner A meets quarter-final winner C, quarter-final winner B meets quarter-final winner D — and the higher league-phase seed retains home advantage in the second leg. Semi-final ties produce the highest sustained secondary-market demand of any round short of the final itself, with lower-bowl bands at top hosts selling out within 24 hours of the quarter-final result. The bracket geography means semi-finals frequently feature the season's two most in-form sides on a collision course set in February.
Format — locked bracket, second-leg seeding
Semi-final pairings are pre-determined from the start of the knockout phase. The higher league-phase seed of each pairing plays the second leg at home, mirroring the structure of the round of 16 and quarter-finals. No new draw takes place between the quarter-finals and semi-finals — both ties are confirmed the moment all four quarter-final winners are known.
What's at stake
Winners advance to the Champions League final, played in late May at a UEFA-designated neutral venue. Losers exit European competition for the season. The final venue is announced years in advance — UEFA's executive committee selects host venues 2-3 seasons ahead, allowing host cities and federations to prepare logistics.
Atmosphere and demand
Semi-final ties consistently produce the season's most-watched away day. Lower-bowl tickets at the seeded club's second leg sell out within hours of the quarter-final winners being confirmed. Hospitality and premium-band inventory commands a 400-800% premium over comparable league-phase pricing at the same venue. Member-priority sales typically absorb 95%+ of stadium capacity at top hosts; verified resale is the standard non-member route.