Scene 1: The Cave of Venus
Naiads, sirens, bacchantes and pairs of lovers take part in a wild orgy, are bombarded with arrows by cupids, then collapse in exhaustion as Tannhäuser, who has been reclining with his head in the lap of Venus, starts up. He has dreamed of the world outside: the sun, the seasons, the birds, which he misses.
Venus reproaches him for not appreciating the delights she offers. She orders him to take his harp and celebrate the joys of love. He obeys, but three times begins in praise of Venus and three times ends on a different theme - his longing for the real world, rather than a life of continuous bliss, for nature and for freedom, even if it brings pain and death - and begs to be allowed to leave. Finding anger, blandishments and entreaties equally unavailing, Venus orders him to go, but warns that his search will be in vain and that he will soon long to return to her realm; all mankind will be cursed if he does not come back. But he is firm in his determination never to return - he will repent and be saved by the Virgin. At this name, the Venusberg vanishes.
Scene 2: A valley near the Wartburg in Thuringia
Tannhäuser finds himself in the valley. A shepherd boy sings a song in praise of Holda, goddess of spring, and a band of pilgrims passes by singing, on the road to Rome. Tannhäuser falls to his knees in prayer, where he is found by the Landgrave of Thuringia and his band of minstrels, Tannhäuser's former companions.
With the exception of Wolfram, who greets him warmly, they treat him with reservation, expecting renewal of the strife and pride in which he had left them. He assures him that he has no belligerent intentions and does not plan to remain. They then beg him to stay, but he refuses until Wolfram mentions Elisabeth, niece of the Landgrave. Wolfram tells him that since his departure, Elisabeth, who had previously listened joyfully to their song contests, has withdrawn in sadness and Tannhuser is persuaded to return to the court.
The hall of the minstrels in the Wartburg
Elisabeth, rejoicing in Tannhäuser's return, joyfully greets the hall of song from which she and he have been so long absent. Wolfram leads in Tannhäuser who falls at her feet. He tells her that he has been far away in strange lands, only able to return to her by a miracle. She wonders why his songs had such power over her that she was so delighted by them and so desolate at his absence, and he replies that the god of love must have touched his strings and then brought him back to her. Seeing their joy at being reunited, Wolfram realises that all hope of Elisabeth is over for him.
The Landgrave is glad to see Elisabeth back in the hall, and asks her to confide in him. She is unable to speak out, but, suspecting her love for Tannhäuser, he hints that the forthcoming song contest will fulfil her wishes.
The court and the minstrels enter and the Landgrave, looking back on former times of peace and war, when the minstrels' songs had gladdened their hearts, offers the theme of love for the song contest and, believing that Tannhäuser will be the victor, promises that Elisabeth will crown the winner - with his heart's desire. Wolfram opens with a song in praise of the cool refreshing stream of love at which the lover must not drink, but only worship. All praise the song, except Tannhäuser, who breaks in with the view that one must drink at the spring, which is eternal and inexhaustible. Elisabeth seems to approve, but the rest of the company shows its disapproval by silence.
Walther takes up the same line as Wolfram - the spring will be defiled if the lover drinks. The company applauds, but Tannhäuser again objects that love is not distant reverence, but something to be held close. Disapproval is expressed more strongly this time and Biterolf angrily declares his readiness to defend women's honor against him with the sword. Tannhäuser answers that Biterolf knows nothing of the soft emotion of love.
The Landgrave intervenes to stop the strife and Wolfram again proclaims his lofty conception of love, provoking Tannhäuser to sing that only one who has dwelt in the arms of Venus knows true love. At his revelation that he has been in the Venusberg, all the ladies except Elisabeth run out of the hall. The angry knights draw their swords on Tannhäuser, who stands as if dazed. Elisabeth runs between them, declaring that although he has wounded her to the heart, he must be spared and allowed to repent. They become calm and Tannhäuser, grieved at what he has done to Elisabeth and at his sin with Venus, accepts the Landgrave's command to join the pilgrimage to Rome.
The valley of the Wartburg
Wolfram comes upon Elisabeth praying at a shrine. She is waiting for the return of the pilgrims and he hopes that she will not be disappointed. Pilgrims return, rejoicing at having received absolution from the Pope, but Tannhäuser is not among them and Elisabeth, begging the forgiveness of the Virgin for having once turned from heavenly things to an earthly love, prays for death so that in heaven she may be able to pray for Tannhäuser's soul. Wolfram begs to be allowed to accompany her, but she indicates that she must travel alone, and climbs up the mountain to the Wartburg as Wolfram prays to the evening star to watch over her.
Tannhäuser returns seeking the way to the Venusberg. He tells Wolfram that although he mortified himself with hard penances on the way to Rome, the Pope had refused him absolution, declaring that one who had sinned as he had could no more be forgiven than his staff could bear leaves. In despair, Tannhäuser calls on Venus, who appears in answer to his summons. Wolfram's entreaties are in vain, till he reminds Tannhäuser of Elisabeth. Tannhäuser comes to his senses, crying Elisabeth's name, and Venus vanishes. He kneels as Elisabeth's body is carried by, begging her to pray for his soul, and dies as more pilgrims return with the news that the Pope's staff has borne leaves.