•Hf data for the magmatic rocks of the Rehoboth Basement Inlier show juvenile input.•Elim Formation and Kangas Metamorphic Complex originated from low-δ18O crustal source.•Two magmatic events within the Rehoboth Province occurred at 1.87 and 2.05Ga.•Crustal reworking within the Rehoboth Province involved mainly Archaean crust. The Rehoboth Province of southern Africa is defined by its smooth magnetic character by contrast to the adjoining mobile belts. It has been slow to yield information about its crustal evolution because most of it is covered by Kalahari sands. A combined microbeam study of U-Pb, Lu-Hf in zircon from metasedimentary and magmatic rocks of the well-exposed Rehoboth Basement Inlier (RBI) provides new constraints on the crustal evolution of the Rehoboth Province. The detrital zircons provide evidence for five U-Pb age groups corresponding to magmatic events within the crust, whereas Lu-Hf zircon data allows estimates of crustal residence age. Zircon oxygen isotope data for the magmatic rocks implies diversity in their genesis. The sparse 3.41–2.45Ga U-Pb zircon age group I (6 zircons) strengthens the concept of an Archaean foundation to the Rehoboth Province, previously suggested from kimberlite xenoliths and granitic cobbles transported by the Dwyka icesheet from further south in the Rehoboth Province. Detrital age group II from 2.15 to 1.92Ga has not been identified in outcropping magmatic rocks. However several Dwyka cobbles have 2.05 ages, similar to the Bushveld Complex and thermal event seen in the adjoining Kaapvaal Craton. This suggests that the Rehoboth Province may already have been attached to the Kaapvaal Craton at this time. Age group II has Lu-Hf isotope character requiring mixing between Archaean crustal source rocks and juvenile mantle material. Age group III (1.92–1.83Ma) corresponds in age to the largely metabasaltic 1870±6Ma Elim Formation, now the oldest dated unit in the RBI. The detrital Lu-Hf data again requires an Archaean crustal source mixing with mantle-derived material. However the magmatic Elim Formation zircons originated from a distinctly more juvenile source than the detrital zircons of the same age (group III), and they have a low mantle δ18Ozrc value of 4.83 (assuming mantle 5.3±0.6). This suggests a mantle or lower oceanic crustal affinity for the Elim Formation, whereas the detrital zircons may have come from a more evolved crustal source located in the continental hinterland. Detrital age group IV (1.83–1.61Ga) corresponds to eight precisely dated volcanic and plutonic rocks which have similar Lu-Hf character and probably provided the detrital zircons. Zircon oxygen isotope values for the magmatic rocks show a considerable range. The sub-mantle values of the 1826±5Ma Kalkbrak Gneiss and 1753±6Ma Marienhof meta-rhyolites (δ18Ozrc 4.30 and 4.31 respectively) are thought to have originated from the same low-δ18O crustal source as the Elim Formation. Three other samples in this group show a trend to higher δ18O values, culminating in a high value of δ18Ozrc 9.35±0.53 for the 1769±6Ma Gaub Valley andesitic, volcanoclastic sample. This trend is thought to reflect addition of low-T altered supracrustal material or high δ18O metasomatic fluids to the source rocks in a geochemically documented subduction setting. The broad detrital age group V (1.33–1.09Ga), found in the one ≤1.1Ga Langberg Formation metasediment investigated, reflects the entire Namaqua Wilson Cycle including rifting and drifting, arc processes, 1.2Ga collision and the post-tectonic 1.1Ga Umkondo plume event. This group shows a large spread of Lu-Hf crustal residence ages from 2.3 to 1.45Ga, reflecting a mixture of sources from Archaean to juvenile Namaqua crust. A 1221±6Ma Gamsberg Granite sample showed 2.2–2.0Ga crustal residence ages and mantle-like δ18Ozrc of 4.99, suggesting that its source was melted Palaeoproterozoic lower crust. Part of the group V detrital zircon population is not known as magmatic rocks in the RBI and was probably derived from the collisional mountain belt in the Namaqua Province to the west of the Rehoboth Province. The Rehoboth Province is thus revealed as an ancient crustal block with possible Archaean foundations, major Palaeoproterozoic events involving mantle additions mixed with reworked Archaean crust, and involving a number of different tectonic settings, culminating with the entire Mesoproterozoic Namaqua Wilson Cycle.