The pirate adventure took a massive £13.4 million during its opening weekend - compared to its nearest competitor's £1.3 million.
Among others out this week were thriller Zodiac, at three with £0.6 million, and Jindabyne, an adaptation of a Raymond Carver short story.
UK and Ireland top 10:
1. Pirates of the Caribbean: At World's End - £13.4m
2. Spider-Man 3 - £1.3m
3. Zodiac - £0.6m
4. 28 Weeks Later - £0.5m
5. Bridge to Terabithia - £0.3m
6. Magicians - £0.15m
7. Cheeni Kum - £0.12m
8. Jindabyne - £0.11m
9. Lovewrecked - £99,013
10. Mr Bean's Holiday - £87,371