The Seiko Museum is located in the special ward of Sumida in Tokyo. 
 
Seiko Museum, 3 Chome- 9 - 7 Higashimukojima, Sumida, Tokyo 131-0032, Japan
 
To make a booking to visit the museum you should go to the official website  - http://museum.seiko.co.jp/, the English page can be found at - http://museum.seiko.co.jp/en/
 
On the site you can make an Internet reservation for 5 people or less for a self guided tour. The self guided tour provides you with an iPad that gives additional information on the different exhibits. 
 
For larger groups, or if you want a personalized tour conducted in Japanese or English, you must call the museum to reserve a tour on +81-3-3610-6248
 
The museum is open from 10:00 to 16:00 each day except Mondays and Holidays.
 
The easiest way to get to the museum is from the Higashi-Mukōjima Station that is on the Tobu Skytree Line. From the station it is an easy 650 meter walk that takes around 8 minutes.
 
The simplest way to get here from most locations in Tokyo is to get to Asakusa and then take the train towards the Tokyo Skytree. The Tobu line station at Asakusa is next to the river near the Azuma-bashi bridge that heads across towards the Asahi Beer Headquarters.
 
When you arrive at Higashi-Mukōjima Station you will go down the stairs to get to the street level. You will see a local map and a sign for the museum that points to the left showing the direct to head.

As you head forward you will pass the Mukojima Elementary school on your right.

You will then get to a T intersection, head to the right. 

Then take the left immediately, essentially just continuing on in the direction you have been traveling since the station.

Head down this road and you will see a park on your right. When you get to the end of this road there will be a major intersection and a bridge.

Cross this bridge and head to the right, down the main road just crossed. Follow this road till you see a red building and a street heading off to the left. From here you will be able to see the Seiko building.

Head down the road and turn left at the end. You will now be at your destination.

Here is a map of this path from the Higashi-Mukōjima to the Museum.

Another alternative way to get to the Museum is from the Minami-Senju Station on the Joban Line. It is about a 1.9km walk from the station and takes about 24 minutes walking.
 
Catch a train to Minami-Senju Station (approximately 7 min from Ueno Station).

When you exit Minami-Senju Station head to the left and you will see a large road overpass and bridges. Cross over the main road and you will then travel south down road 464 for approximately 200m then turn left onto Meiji Dori (306).

Head along Meiji Dori for around 8min and cross the bridge over the Sumida River. Once across the river at the first set of traffic lights, turn right and you will see the Museum. Here is a map of this route.