Abstract: Different from extensively reported carbon nanotubes‐polyamide (PA) composite membranes, this work reports the scalable, low‐cost manufacturing of metallic single‐walled carbon nanotubes network supported PA reverse osmotic desalination membranes. Metallic single‐walled carbon nanotubes (SWCNTs) separated from high‐pressure carbon monoxide conversion (HiPCO) SWCNTs with a diameter ranging from 0.6 to 1.2 nm are deposited on polyethersulfone (PES) films by replacing surfactants around SWCNTs dispersed in aqueous solution, for supporting uniform and smooth sub‐10 nm PA nanofilm formed through aqueous‐organic bilayer interfacial polymerization. The industrial scale manufactured PA/SWCNTs/PES desalination membranes (508 mm × 915 mm) are rolled into spiral wound elements without damage through cutting, gluing, and rolling. The desalination tests on flat PA/SWCNTs/PES membranes exhibits 30 l m−2 h−1 (LMH) under 17.2 bar with 98.45% salt injection when fed with 2000 ppm NaCl at pH = 9. The normalized permeate flux of PA/SWCNTs/PES spiral wound elements is ≈17 LMH under 13.8 bar with 90% salt injection underfed with 2000 ppm MgSO4 at pH = 9–11 condition. The high‐performance sub‐10 nm smooth PA/SWCNTs/PES desalination membranes are fabricated with materials savings and can promote low operation costs compared to conventional 50–100 nm crumpled PA films on any supporting substrates.