The 24-year-old has two years left on his current deal, but he is keen to move to a better league, and Ajax Director General Edwin van der Sar and Sporting Director Marc Overmars are willing to let him go for around £26 million.
Onana has plenty of suitors already, with Barcelona, Chelsea and Paris Saint-Germain all interested in his services.
Tottenham are looking to get a long-term and quality replacement for skipper Hugo Lloris, and have identified the Ajax star as their man.
They are already in contact with the goalie, but it remains to be seen if they can convince him to move to North London this summer given the calibre of competition they face for his signature.
Missing out on next season’s Champions League will deal a massive blow on their chances, and the fact that they haven’t won a trophy in 12 years could also be a major deterrent.
Spurs need to boost their squad this summer if they are to have a chance of mounting a strong challenge for major honours next term and going forward, and landing a top goalkeeper will come handy given Lloris’ occasional errors.
However, they might have to look elsewhere as they don’t have the most realistic chances in the race for Onana’s signature.