KC Hotel in Sabana Sur. Day pass includes access to heated pool (9:30 - 5:30) and executive lunch at the hotel restaurant. Book or get more info via WhatsApp at the link below.
https://www.kchotelsanjose.com/There are also various municipal pools that are cheaper and much colder.
Piscina González Víquez
4080 9900 ext. 2010
https://maps.app.goo.gl/SrbPpvb8EgNYMnUZ8?g_st=icGo for the heated option, littlejimmy will thank you.
Also, if you are going to do this, pack a rashguard and swim cap if you are bald or have thinning hair. CR is 9 degrees off the equator.