Switzerland's second largest city also rates as the priciest in the world when it comes to ordering a burger, fries and soft drink, according to online accommodation booking website hotels.com.
The website calculates that a club sandwich will set you back £19.94 ($31.39 at current exchange rates) in a Geneva hotel rated three to five stars.
That's slightly less than last year but still almost three times as much as in hotels of the same calibre in Mexico City (£6.37) and well ahead of the next dearest place, Paris, where the typical American menu item averages £15.90, hotels.com says.
In Rome, meanwhile, you could order one for an average price of £9.47, 32 percent less than in 2014.
The triple-decker toasted sandwich, typically containing sliced poultry, bacon, lettuce, tomato and mayonnaise, is not always readily found in Geneva or Paris hotels.
And, if you're visiting such cities is that the gastronomy you are really seeking?
But hotels.com says comparing the price of the staple item in US hotels helps visitors understand the costs associated with hotel dining in hotels worldwide.
And for 2015 it has added other typically American reference points to compare dining prices: a burger meal (consisting of a burger, chips and soft drink); a cup of coffee and a glass of house red wine.
Burger meals cost the most in Geneva (£24.64), followed by Oslo (£20.33) and Hong Kong (£19.93), where club sandwiches are the third most expensive.
Such meals are cheapest in Bogota, Colombia (£7.67), according to the survey.
You have to dig deepest for a glass of house red wine in Singapore, where you will pay almost as much (£9.11) as for a club sandwich (£11.10).
That same red wine will cost you £8.35 on average in higher end Paris hotels, the second most expensive price — surprising, considering how cheap wine is in French supermarkets.
Wine in Geneva hotels (£7.91) is cheaper than in Seoul (£8.87), Beijing (£8.12), Oslo (£8.03) New York (£8.02 and Hong Kong (£8.01).
The incontestable best deal for wine is in Madrid, where an average glass of the house variety sells for £2.95, hotels.com says.
Hotel coffee in Geneva rates as the most expensive in Europe at £4.04 a cup but it remains a bargain compared to Asian cities such as Seoul (the most expensive at £6.34), Tokyo (£5.54) and Beijing (£5.01).
But for visitors ordering a burger meal (£24.64), cup of coffee, glass of house wine and a club sandwich, the average bill comes to £56.52 in Geneva hotels, making them the most expensive in the world.
The hotels.com survey compares prices at mid- to upper-priced hotels in 28 cities.