The hotel offers 123 rooms in total. Each of these is designed to make best use of subtle colors and natural light.
In the Garden Wing, guests can choose between the standard queen room, with its city view, and the superior king room, with its view of the gardens, and in the Main House, they can choose the deluxe king room, which may overlook the city's government buildings or the hotel's period gardens. Rooms range in size from 30 to 40 square meters and are all non smoking.
Every room has free Wi-Fi Internet, video conferencing, multi-line telephones, two armchairs, personalized voicemail with remote access, television with movies on demand, a writing desk with Merrion stationery, individually controlled air-conditioning, and a minibar.
The queen room can accommodate 2 adults and 1 child. It has a large bathroom featuring Italian carrera marble and separate bath and shower, as well as a bidet. A radio and refrigerator, as well as clothes press, safe and stereo system are also available in the room.
All of the same features are offered in the two king rooms; the difference lies in the size of each room and the views from the windows.
The hotel offers 19 suites. These one- or two-bedroom suites are perfect for families. In the bedrooms, one can request either a king bed or twin beds.
Each suite has a sitting room that includes a four-seat dining table, a sofa, and two armchairs, as well as a coffee table with a selection of magazines and a Nespresso coffee machine.
Apart from this, all of the same amenities offered in the smaller rooms are also available in the suites.
In the Garden Wing, guests can choose the Garden Wing Suite, which is 82 square meters wide and overlooks the city, or the Penthouse Suite, which is 204 square meters wide and commands breathtaking views of Dublin, the Wicklow Mountains, and the period gardens. The Penthouse Suite is the largest of all the hotel's suites, with the Garden Wing Suite following as second-largest. The Main House's suites are all much smaller, ranging from 53 square meters to 73 square meters.
In the Main House, the Merrion Suite overlooks the gardens as do many of the Junior and Specialty Suites, though some of these can also overlook the city's government buildings.
The Garden Wing Suite features a king bed in one bedroom and twin beds in the second bedroom. An extra rollaway bed or crib can be placed in each room, on request. The suite can accommodate 2 adults and 4 children.
The Junior Suite can accommodate 2 adults and 1 child, featuring one king bed with the option to include a rollaway bed. The same applies to the Merrion Suite.
Called the Specialty Suites, the Lord Monck and Lord Antrim Suites are found on the upper floors of what was once Nos. 22 and 23 Upper Merrion Street. They feature plenty of natural light. The Lord Antrim Suite overlooks the city's government buildings, and the other suite overlooks the hotel's landscaped gardens. Both suites feature a lovingly restored version of their original rococo plaster. The curved ceiling in the Lord Monck bedroom boasts avian and floral motifs.
Specialty Suites have a king-size bed, as well as the same sitting room and dining room arrangements found in the other suites. A decorative Georgian fireplace completes the picture of stylish comfort. The Lord Monck suite includes a cozy additional bedroom that can double as an office or gym or even as an extra dining room.
The Penthouse Suite, typically frequented by heads of state and celebrities, features private access and security. Up to 5 guests can be accommodated in its three bedrooms. The master bedroom features a king-sized bed, while the second room has twin beds and the third has a sofa bed. In addition, a rollaway bed or crib may be placed in each room, upon request.
On the ground floor of the split-level suite, the two bedrooms are en-suite, featuring separate bathtubs and showers. Georgian-inspired fabrics are used on the walls of the rooms to retain the hotel's historical connection. On the upper floor, one can find the carpeted living and dining rooms. The marble-floored kitchen features state of the art equipment to allow home cooks to indulge themselves. The suite also has its own music room and a private roof terrace overlooking the hotel’s period gardens. The Penthouse Suite offers all the same features found in the other rooms and suites; the exceptions are that it includes two seating areas instead of one, a fully equipped kitchen, a study, and two mini bars. It also includes a private study, and the dining table can accommodate six people, instead of four.