We stayed here for two nights at the start of a trip to Gibraltar. It is opposite the port and quite old and tired, but we found our room clean and it suited our purpose.
The garage car parking was useful and we travelled to Gibraltar by bus - the bus station is about 5 mins walk from the hotel. This worked very well as the bus station at La Concepcion is close to the border.
The town of Algerciras is unpretentious and worth a look around.

Do not believe every thing you hear.
I stayed there in July for a couple of days before going to Morocco and again when I returned from Morocco.
Unfortunatly I was requested to pay in advance for this hotel or I would not have stayed there the second time. i had booked 2 rooms connecting
On my first visit the A/C was not working ( 36 Deg. in the shade )
I was moved to three different rooms before getting one that was sea facing. and not connected. I was told that the A/C JUST JUST packed up and it will be fixed shortly.
On my return trip, 7 days later, I was told the same lie BUT by a different person at reception. BUT I was given a fan for each room. Management refused to even speak to me about this let alone acknowledge their lies and apologies.

Great location. Within walking distance of port, bus, train and centre of town. Staff are nice and helpful and spoke English. It is a very old hotel and some lights and electricity was not working. My room was clean and had a view of the port.

Good for a cheap night in transit or the adventurous.

My guide book shows Al Mar as 3-star-hotel. OK, everybody, it is 3 star in Algeciras, definitely not world standard.

It is spacy, but really old, or I should say that it is an old hotel, hence it is spacious. A/C didn't work in my room. Some lamps were dead.
They might need a overall repair !? It is not maintained very well, honestly.
Breakfast was OK, it is basic line.
Al Mar should not be categorized as a hotel.

If you are planning to take a ferry to visit to Morocco, the location would be good, because the ferry terminal is just in front. Information center, bus station are also close from hotel, but 40 euro per night !? I don't think so.
There are many hostels, pensions on back street. If you go to Algeciras in low season, you probably can find more reasonabe place to sleep upon your arrival.

I used Viajes Transafric to book one day tour for Tangier, this agent is somehow related to Al Mar. You have to check before booking, but you might be able to get discount to stay in Al Mar if you use Viajes Transafric ( check their website)