Update 2019: The Mercure Siam Bangkok is located near Siam Square, one of my favorite locations in Bangkok. The Mercure Siam has a rooftop pool and gym with nice views, a nice Executive Lounge for an upscale feel and very modern rooms, all at very reasonable prices. It’s a great choice, especially for Accor LeClub elite members. Find out what to expect in my review of the Mercure Siam Bangkok! 
Location: The Mercure Siam is located right next to the BTS National Stadium station, a short walk from the MBK mall and the Siam BTS interchange. It gives you easy access to anywhere in Bangkok by train, making it convenient for the visitor, because you can avoid the crazy traffic! You can also reach the connected malls on Sukhumvit by foot! Check out my tips How to get around Bangkok why BTS is such a good idea!
Service: At ground level, you will be welcomed by bell staff who can assist with your luggage and you’ll be sent to the reception on the 9th floor for check-in. As an Accor LeClub Platinum member, I was escorted to the club lounge for check-in. The lounge staff had my paperwork ready, I was offered a cold drink while signing the forms.
Staff at the lounge was very friendly and helpful throughout my stay. They were attentive during the lounge happy hour and breakfast, befitting the lounge of a much more expensive and upscale hotel – a very luxurious touch for a mid-level hotel! They inquired about my stay and plans, offering assistance along the way.
Housekeeping did an equally good job and cleaned my room thoroughly and quickly each day. The staff at the rooftop pool bar was just as friendly and attentive. The restaurant was professional, but the crowds didn’t allow them the time to be as attentive as at the lounge. The buffet was always well stocked and tables cleared quickly.
Rooms: The Executive Rooms at the Mercure are nice and modern. They are large and held in a dark grey decor with a purple touch of color. The room had a queen bed, as well as a couch than can be converted to another bed. It is outfitted with a TV, coffee/tea facilities and a safe. 
The bathroom has nice tiles and a large, glass enclosed shower with a glass wall to the bedroom. If you don’t appreciate that feature, there is a sliding door to cover the glass for more privacy – a nice feature to make the room appealing to more people. They do have rooms with a connecting door to a room of the same size with two twin beds, making it great for families. The Executive rooms also offer bathrobes and slippers, a pod coffee maker in addition to the kettle and a sound station for your phone!
The free WiFi internet in the room was reliable and fast at an average speed of 17.1Mbps! You can easily work or stream video at that speed!
On my return visit, I was upgraded to a Suite! You enter a small living room, with a seating area and a work desk. You’ll also find a mini-bar, coffee and tea facilities as well as pod coffee maker for excellent espresso and plenty of free water. You’ll have a wall mounted TV to watch from the couch.
A door separates the bed room and bathroom. The bedroom is fairly small and has a queen-size bed, with comfortable sheets, comforter and pillows. The suite is located on a building corner and there are windows all around, so you can make it very bright and have a view over the National Stadium across the road.
There is another desk with task chair, as well as a large wardrobe that holds the laptop size safe, bathrobes and slippers. You’ll also find a luggage bench and there is a second, wall-mounted TV.
The bathroom is very large. It has a single vanity with a counter-top large enough for any amount of toiletries anybody could bring. On the opposite side are toilet and shower cubicles, separated by a glass wall. They share a sliding glass door, so one is always open, the other closed. There is a window to the outside, making the room bright and giving you a view from the shower.
I enjoyed the extra space of the suite, giving me a chance to hang out in the room, without having to sit on the bed. It’s especially worth while for a longer stay!
Restaurant & Amenities: The Executive Lounge on the 24th floor is a comfortable space with a small buffet area, bistro style seating on one side and living room style seating on the other. There are also computers and a printer as a mini business center and a large outdoor patio. The lounge offers a free continental breakfast in the morning, with pastries, fresh fruit and yogurt, coffee, juice as well as a number of hot dishes for a full breakfast.
They have light snacks during the day and a happy hour in the evening, with a full bar of soft drinks, beer, wine and hard liquor as well as cold and warm food – making for a better spread then some more upscale hotel lounges!
The Mercure Siam Bangkok has a gym and pool on the rooftop. The pool is long and narrow and has an infinity edge overlooking the Bangkok skyline. There are loungers off to the side, so you can relax after a day of sightseeing or shopping.
If you enjoyed the Thai food a little too much, you can work out in the gym overlooking the pool with a selection of cardio and weight equipment. It’s small, but will allow for a basic workout and you have a nice view over the city.
You will find a bar at the 9th floor lobby level and a restaurant that is shared with the ibis on the 8th floor. I tried the bar on the 9th floor and the staff was friendly and attentive, although I had the bar pretty much to myself! That’s a solid amenity offering and I was especially surprised by the Executive Lounge which I did not expect at the Mercure! The Mercure Siam is new and in great condition all around. The rooms showed little wear and tear and the same is true for the lounge!
Value & Rewards: I booked the Mercure Siam Bangkok direct with Accor for $57/night, even less than during my last stay at $63/night. As an Accor LeClub Platinum member, I earn a reward rate of 8.7% in Accor LeClub points. I earned an additional 3% by paying with my Citi Prestige credit card and 4% by going through the TopCashback portal. You can find the current prices at the Mercure Bangkok Siam here!
As an Accor LeClub Platinum member, I received a two-category upgrade to a full suite, access to the Executive Club Lounge with breakfast, coffee & tea and an evening happy hour, as well as a welcome drink at one of the bars. A large fruit welcome amenity was delivered to my room. Altogether, this is exceptional elite treatment and goes well above & beyond of the rules of the program, making the Mercure Siam Bangkok one of the few hotels that wow loyal guests!
Bottomline: At a price of only $57/night I got a modern room at a new hotel in one of the best locations of Bangkok with a lot more amenities than you’d expect from a hotel in this category: The Executive Lounge access, free breakfast and happy hour make this a much more luxurious stay than other hotels at this price! There are few hotels with lounges in this price range, making the Mercure Siam a standout -especially when you can book it for less during the frequent Accor sales. There are many good hotels in this price range in Bangkok – I consider it the “sweet spot” of best value for your money – and the Mercure Siam is one of the best in this category, I recommend it and plan to stay again myself in the future!