Do I need to adjust any settings when transitioning between countries, for instance, from Singapore to Malaysia?

No, the transition is entirely automatic and seamless with WorldESIM. As you cross an international border during your Asian tour, perhaps from Singapore into Malaysia, your device will intelligently connect to the optimal local carrier in the new country without requiring any manual intervention from your side. Just ensure that your 'Data Roaming' setting is enabled on your device, and WorldESIM handles the rest, keeping you connected effortlessly.