A cadet cruise was a training evolution for Starfleet cadets where they served aboard a Starfleet starship or facility for a period of time with closely supervised duties and expected to perform as if they were a member of the crew.
They could last for weeks\, months and on some occasions in excess of a year. Though in the latter case a commission at its completion vice returning to the Academy as a cadet was the standard.
Traditionally a cadet cruise was undertaken during a cadet's third year at the Academy and lasted 2 to 5 months.
Gedna Tachion 2335 - USS Stargazer
Patricia Rivers - 2335 - USS Repulse
Roger Diect - 2340 - USS Finian
Abigail Harris - 2365 - USS Odin
Michael Garrett - 2366 - USS Malawi
Mala Corwin - 2369 - Saturn Station One
Spencer Stone -2369 - Memory Alpha