This paper presents the implementation of next-to-leading order (NLO) calculations for single-top quark production in the $Wt$-channel using the POWHEG method, interfaced with Shower Monte Carlo programs. The authors compare their results with those from MC@NLO and show results obtained using the PYTHIA shower. The main focus is on the implementation details of the POWHEG-BOX package, which automates the NLO calculation and integrates it with parton showers. The paper discusses the challenges of dealing with interference effects between $Wt$ and $t\bar{t}$ production, which are addressed using two definitions of NLO corrections: Diagram Removal (DR) and Diagram Subtraction (DS). The results are validated by comparing them with MC@NLO and PYTHIA, showing good agreement. The paper also explores the impact of typical cuts on the $Wt$-channel process and concludes by highlighting the completion of the POWHEG implementation of all single-top processes relevant for Higgs searches.This paper presents the implementation of next-to-leading order (NLO) calculations for single-top quark production in the $Wt$-channel using the POWHEG method, interfaced with Shower Monte Carlo programs. The authors compare their results with those from MC@NLO and show results obtained using the PYTHIA shower. The main focus is on the implementation details of the POWHEG-BOX package, which automates the NLO calculation and integrates it with parton showers. The paper discusses the challenges of dealing with interference effects between $Wt$ and $t\bar{t}$ production, which are addressed using two definitions of NLO corrections: Diagram Removal (DR) and Diagram Subtraction (DS). The results are validated by comparing them with MC@NLO and PYTHIA, showing good agreement. The paper also explores the impact of typical cuts on the $Wt$-channel process and concludes by highlighting the completion of the POWHEG implementation of all single-top processes relevant for Higgs searches.