Splendid isolation is a term used to describe the 19th-century British diplomatic practice of avoiding permanent alliances from 1815 to 1902. The concept developed as early as 1822, when Britain left the post-1815 Concert of Europe, and continued until the 1902 Anglo-Japanese Alliance and the 1904 Entente Cordiale with France. As Europe was divided into two power blocs, Britain became aligned with the French Third Republic and the Russian Empire against the German Empire, Austria-Hungary and the Kingdom of Italy.

The first Anglo-Japanese Alliance was an alliance between Britain and Japan. It was in operation from 1902 to 1922. The original British goal was to prevent Russia from expanding in Manchuria while also preserving the territorial integrity of China and Korea. For the British, it marked the end of a period of "splendid isolation" while allowing for greater focus on protecting India and competing in the Anglo-German naval arms race. The alliance was part of a larger British strategy to reduce imperial overcommitment and recall the Royal Navy to defend Britain. The Japanese, on the other hand, gained international prestige from the alliance and used it as a foundation for their diplomacy for two decades. In 1905, the treaty was redefined in favor of Japan concerning Korea. It was renewed in 1911 for another ten years and replaced by the Four-Power Treaty in 1922.