In August 1935, the King and Queen went incognito to Switzerland on holiday. Prince Albert remained in Brussels. Only one year old, he was considered too young for the journey. Joséphine-Charlotte and Baudouin had travelled with their parents to their holiday home, Villa Haslihorn in Horw, Switzerland. The children were sent back to Belgium with their nannies on 28 August. On 29 August 1935, the King and Queen decided to go for a last hike in the mountains before returning home. Their chauffeur was sitting in the back of the Packard One-Twenty convertible, the King was driving and the Queen looking at a map. As the Queen pointed out something to her husband the car went off the road, down a steep slope, and slammed into a pear tree. Queen Astrid had opened her door to try to get out, but she was thrown out upon impact. Her body collided with the trunk of the tree, while the car slammed into a second tree. King Leopold was thrown out of the car as well, but he was only lightly injured. The car went on, only to stop in a lake. It was 9:30 am on 29 August 1935. The Queen died from her injuries at the scene of the accident at Küssnacht am Rigi, near Lake Lucerne, Schwyz, Switzerland.
Queen Astrid is interred in the royal vault at the Church of Our Lady of Laeken, Brussels, beside her husband, King Leopold III of the Belgians, and his second wife, Princess Lilian of Belgium.