Coastal ecosystem engineers such as mussels, oysters, salt marsh grasses and seagrasses, typically shape their environment by ameliorating stressors when they grow beyond a critical population size. In doing so, they not only facilitate themselves, but also provide habitat for diverse communities which, in turn, can engage in reciprocal interspecific facilitation. Over the last decades, anthropogenic disturbances have caused rapid degradation of coastal ecosystems, emphasizing the need for their restoration. Although the importance of both inter- and intraspecific positive interactions have been confirmed in small-scale experiments, their combined potential remains to be tested in application-scale restoration experiments. Here, we examine whether restoration aimed at simultaneous recovery of both facilitation types can increase restoration yields of the seagrass Zostera marina. We conducted a full factorial experiment by manipulating patch size to test for intraspecific facilitation effects and co-introduced the epiphyte grazing snails Littorina littorea to investigate interspecific facilitation. We found that the effect of including intraspecific facilitation on restoration yields was highly dependent on the hydrodynamic exposure conditions at the restoration site. Large patches in the most exposed sites showed a 40% increase in seagrass restoration yield compared to small patches, while at sheltered sites, large patches performed up to 60% worse than small ones. Interspecific facilitation, on the other hand, increased success yields by 73% on average. Moreover, plots in which L. littorea had survived over the winter locally performed over 20 times better than their non-co-introduced counterparts. Our study is the first to demonstrate that co-introduction can serve as a successful large-scale restoration strategy. Additionally, we highlight that integration of both inter- and intraspecific facilitation into restoration designs can be a powerful approach to increase coastal restoration success. However, we emphasize that these strategies should be applied specifically to counter environmental stressors, as they may have adverse effects themselves in environments without such stressors.