The Azerbaijan Grand Prix begins with first practice on Friday. The last race was held in Madrid for the first time, but the track faced criticism from several drivers, including world champion Lando Norris. Others categorised the race as 'a procession'.
Alonso was critical not just of the MadRing circuit in statements made to Motorsport.com, but said that a number of tracks were not conducive to exciting races.
"Silverstone, an incredible track, is no longer fun," said Alonso.
"Spa was almost embarrassing going through Eau Rouge; Suzuka, the 130R... There are circuits that have been assassinated this year."
The Aston Martin driver was positive about the current popularity of Formula One, but also spoke in favour of more changes to the engine output.
Formula 1 has announced changes for 2027 regarding the balance of output between the electric component and the combustion component.
Alonso would reduce the immediate acceleration provided by the electric component in favour of maintaining speed for longer. It is a matter, he says, he regularly discusses with Formula One CEO Stefano Domenicali and Mohammed Ben Sulayem, the president of the International Automobile Federation.
"Maybe from the cockpit, behind the wheel, especially if you drive other categories or have experienced other Formula 1 cars, there's a bit of frustration," Alonso said.
"I don't have all the information. We have to trust in the sport."