When in Lausanne, almost every direction given is either toward or away from Ouchy (ooo-shee), or in other words, downhill toward the lakefront/port (a former fishing village named Ouchy) or uphill toward Old Town and the rest. There's much to see and do here, and arriving is easy via the nearby Ouchy-Olympique M2 Metro stop.
Our family of three enjoyed strolling through the tree-lined park spaces, playing on the large ship-shaped playscape, getting a snack at the food stand, contemplating some interesting sculptures and architecture, seeing the boats arrive & depart, avoiding large seabirds, admiring the adjacent 12th century Château d'Ouchy, and watching a few matches of chess & checkers.
If you're planning to take one of the famed CGN ferries around Lac Leman http://www.cgn.ch/en-gb/, your boat will depart from here. Be sure to arrive at least 20 minutes before departure. Sample timetable: http://www.cgn.ch/media/316906/affiche-horaire-hiver-2018.pdf
Other boating options departing from Ouchy depending on the season include the solar-powered Aquarels http://www.lesaquarelsduleman.ch and the historic sailboat La Vaudoise http://ww.lavaudoise.com.
More to do in Ouchy:
https://www.myswitzerland.com/en-us/ouchy.html
https://www.timeout.com/switzerland/things-to-do/ouchy-promenade read more