In the Finnish language, the instructive case has the basic meaning of "by means of". It is a comparatively rarely used case, though it is found in some commonly used expressions, such as "omin silmin" -> "with my own eyes".

In modern Finnish, many of its instrumental uses are being superseded by the adessive case, as in "minä matkustin junalla" -> "I travelled by train."

It is also used with Finnish verbal second infinitives to mean "by ...ing", for example "lentäen" -> "by flying", "by air".