<p>This paper extends our previous work on spreadsheet-based steady-state groundwater flow modeling to include transient conditions. Using a step-by-step Excel implementation, a numerical solution for transient groundwater flow in a confined aquifer is presented, highlighting the spreadsheet’s educational value in understanding complex groundwater flow phenomena. Implementing transient flow in an easy-to-visualize and interactive way in Excel was not trivial and required the use of macros created with Visual Basic for Applications. Although the actions of the macros were simple to describe, their implementation was challenging. For this reason, we used ChatGPT as a coding companion, which provided the code after being provided with carefully designed prompts.</p>