Yes, you can put an infant car seat in a Wonderfold Wagon, but it requires a specific, brand-compatible car seat adapter. In recent years, Wonderfold has released adapters that are compatible with their W2 and W4 series (Elite and Luxe models). These adapters typically click into the frame where the bench seats normally sit. Once the adapter is installed, it is compatible with popular infant car seat brands such as Nuna, Cybex, Maxi-Cosi, Graco, and Britax. A key feature of the Wonderfold adapter is its ability to rotate 360 degrees, allowing the baby to face you or the world. On the larger W4 models, you can even remove both bench seats to accommodate two car seat adapters simultaneously, making it a viable option for twins. It is important to note that you should never simply place a car seat loosely inside the wagon without an official adapter, as the seat could tip or slide during movement, posing a significant safety risk to the infant.