The only remaining areas of pristine 3.6–2.7 Ga crust on Earth are parts of the Kaapvaal and Pilbara cratons. General similarities of their rock records, especially of the overlying late Archean sequences, suggest that they were once part of a larger Vaalbara supercontinent. Here we show that the present geochronological, structural and palaeomagnetic data support such a Vaalbara model at least as far back as 3.1 Ga, and possibly further back to 3.6 Ga. Vaalbara fragmented prior to 2.1 Ga, and possibly as early as 2.7 Ga, suggesting supercontinent stability of at least 400 Myr, consistent with Neoproterozoic and Phanerozoic analogues.