Silver nanowire (AgNW) films have beenstudied as the most promising flexible transparent electrodesfor flexible photoelectronics. The wire−wire junction resistancein the AgNW film is a critical parameter to the electricalperformance, and several techniques of nanowelding orsoldering have been reported to reduce the wire−wire junctionresistance. However, these methods require either specificfacilities, or additional materials as the “solder”, and often haveadverse effects to the AgNW film or substrate. In this study, weshow that at the nanoscale, capillary force is a powerful driving force that can effectively cause self-limited cold welding of thewire−wire junction for AgNWs. The capillary-force-induced welding can be simply achieved by applying moisture on the AgNWfilm, without any technical support like the addition of materials or the use of specific facilities. The moisture-treated AgNW filmsexhibit a significant decrease in sheet resistance, but negligible changes in transparency. We have also demonstrated that thismethod is effective to heal damaged AgNW films of wearable electronics and can be conveniently performed not only indoorsbut also outdoors where technical support is often unavailable. The capillary-force-based method may also be useful in thewelding of other metal NWs, the fabrication of nanostructures, and smart assemblies for versatile flexible optoelectronicapplications.