Finally got myself to Venelles to try out the Centre Aquatique Sainte Victoire …and had a lovely swim, once I’d figured out what to do with my ticket (goes in metro-style gate), how to negotiate the ‘zone de déchaussage’, how to work the key-pads on the lockers and finally how to find the pool itself (lots of doors, nearly ended up in the gents).
But it’s worth the faff; the first time at a pool is always a logistical challenge. The main pool is 33m x 8 lanes, two of which were open to the public. There is a smaller pool, plus a play-pool with whirlpool/tub. Outside there’s a 50m x 3 lane pool plus sports/picnic/play area. All well-heated.
The outdoor pool – heated to 28 degrees on my visit
It’s beautifully designed, and a wonderful experience to swim up and down outside in January admiring the nearby Montagne Sainte-Victoire.
Reports on Tripadvisor have criticised the standards of cleanliness, small number of changing cabins, and too few showers. I found it all fine, but it was mid-week in January. I should imagine a couple of school parties in there would fill the changing area quickly. My only gripe was the hairdryers, few of which worked.
It’s 4€ entry, and you have to wear a bathing hat during the winter. I have yet to figure out this French business with swimming hats – the locals all seem to know when they can turn up without them.
It’s open daily but the opening hours are varied, for instance it closes at lunchtimes at weekends. Details here: https://www.guide-piscine.fr/bouches-du-rhone/piscine-sainte-victoire-a-venelles-3329_P, but probably best to phone first to check. Number for pools in Aix is 0810 008 060.
aixcentric 
Their app (http://www.agglo-paysdaix.fr/sports/piscines/appli-piscines.html) is highly recommended: all opening hours, photos, fees, and even short-term changes (like closure for technical difficulties) in real-time.
Thanks so much. I couldn’t find a comprehensive website.
First time at a pool is always a logistical challenge! Lunch time work swim at the Guildford Olympic pool, face full of make up, sparkle ear rings, work hair up in a top knot, summer swimming suit on. I stood at the side of the pool to work out which lane to go and thrash out 40 lengths. The life guard said to me, in my get up, are you looking for the aqua class madam?
He thought you were too cool for the pool!!