By default, you need at least 30 in skill to enter the highscores. However, since the highscores "only" list the top 1 million characters, some of the highscores have higher limit to enter than the default 30 (which is true for all non member skills).

Here is list of skills required to enter the highscores. If there is no limit listed for the skill, it means that that there is less than 1 million characters with 30 or more in the skill, so you only need level 30 to enter the highscores.

This list is udpated mostly on weekly basis (due to expense of construction)