The paper aims to provide an update on the development of multi-physics coupling for the Monte Carlo code Serpent with the subchannel thermal-hydraulic solver CTF for multi-physics modeling and simulation of pressurized water reactors in principal and as part of the activities of the Organisation for Economic Co-operation and Development, Nuclear Energy Agency (OECD/NEA) Tennessee Valley Authority (TVA) Watts Bar Unit 1 (WB1) multi-physics, multi-cycle depletion benchmark team in particular. Serpent/CTF are coupled to perform steady-state and cycle depletion exercises of the benchmark. Serpent/CTF is an external coupling based on Picard iteration, and it utilizes the Serpent capabilities to communicate with an external solver via the signal library in Python. Serpent/CTF coupling is tested on a three-dimensional (3D) assembly-level problem at nominal conditions as well as on a full-core problem at nominal conditions with xenon equilibrium and verified against the Virtual Environment for Reactor Applications (VERA) code system. The test cases include Problem 6 from the Consortium for Advanced Simulation of Light Water Reactors VERA Core Physics Benchmark Progression Problem Specifications and Exercise 2 of the OECD/NEA TVA-WB1 benchmark. The compared integral parameters are keff, critical boron concentration and local distributions of power, fuel temperature, channel liquid temperature, and channel liquid density. The comparative analysis shows good agreement, with a keff difference of −74 pcm, critical boron concentration of −8.86 ppm, mean difference of 0.01 for the corewise normalized pin power, 0.17 K for the channel liquid temperature, and 0.45 kg/m3 for the channel liquid density. Serpent/CTF calculations face difficulties in pin fuel temperature convergence below 1% and in overestimating the pin fuel temperature in a few locations.