My wife & I stayed at the Colombia for 3 nights in May en route to a further 7 days holiday in Venice.
We had picked the hotel after much study of TripAdvisor and were very happy with our choice.
The site is perfect, about 100 yards away from Via Carducci, which is the main road in Trieste and very near the Station which we were to use for our travel to Venice.
It took about 20 minutes to walk to Piazza Unita
The rooms were spotless albeit very compact and the small breakfast room coped with everyone (mainly business travellers).
Some street noise if one opened the windows but this is a working city.
We were intrigued by the cupboard that contained ( apart from plenty of room for clothes) a TV, Wall Safe and a minibar which was well stocked (see pic).
The reception staff were friendly & helpful and the decor was, as my grandkids would say, cool !
We would have no hesitation in recommending this place to anyone wanting a very reasonable hotel for a short stay.

Lovely central hotel,but in a quiet street so very little traffic noise.Staff couldn't be more helpfull or friendly.Close to all the sites,good breakfast and excellent maid service.Fantastic powerfull shower,everyone we spoke to staying in the hotel commented on the showers!

Situated approximately 5-10 minutes walk from the Train/Bus Station, it provides comfortable accomodation but like most hotels in Europe you will not be disappointed if you don't expect too much.
The reception area has a modern-art design feel. The man at reception who checked us was not fluent in English but I found him to be very helpful when we asked him about tourist sites and transport information.
Our double room was quite spacious, with an area for a table and large wardrobe.
Trieste is a small town and from the hotel it is within walking distance to sites including: Canal Grande, Piassa Verdi and Piassa dell'Unita d'Italia. Otherwise a bus station, Piazza Oberdan can take you to the Grotta Gigante (largest tourist cave in the world...this is another place worth going to) and Castello Miramare.
I had a pleasant stay at Colombia Hotel and will recommend it to travellers.