Since the inaugural Comrades Marathon in 1921, ultramarathons have witnessed remarkable growth, with a recent surge in both participation and spectator interest. As performance improvement becomes a priority for researchers and ultramarathon runners, understanding pacing strategies, which greatly impact performance, is essential. Pacing strategies for ultramarathon runners can differ substantially based on factors such as age, distance, performance level, and the competition environment. These strategies can help overcome speed drops, especially when running on mountainous or flat terrain, and aid in implementing precooling strategies for improved running. However, no study has fully explored the distinct pacing techniques required for ultramarathons on hilly terrain compared to level roads or tracks. This review aims to provide researchers, coaches, and ultramarathon competitors with a better understanding of pacing processes and strategies across various terrains. It synthesizes effective pacing strategies from existing literature on mountain and track ultramarathons, highlighting similarities, differences, and potential gaps in knowledge. By doing so, this review aims to help ultramarathon participants more effectively comprehend and apply pacing tactics across a range of terrains.