Two very different races. Here's every stat, side by side, to help you pick.
Indicative — based on GPX data. Both courses normalised to start at 0m.
✓ marks the better number on that stat.
London is one of the fastest Majors in the world; Sydney is one of the hardest. London's course gains just 85m across its Thames-side route, while Sydney climbs 313m over the Harbour Bridge and the hills around the Opera House — a gap that shows clearly in the course records, London's 1:59:30 world record against Sydney's considerably tougher 2:06:06.
Sydney is also the newer and smaller of the two, with roughly 33,000 finishers against London's near-60,000, giving it a more intimate feel despite its recent promotion to full Majors status. If a fast, flat course and the world's biggest marathon crowd is what you want, London wins easily; if you'd rather run over one of the most photographed bridges on earth and finish by the Opera House, Sydney is worth the harder climb.