Anyone arriving in Japan from a foreign country must arrange for transportation in advance under current government guidelines.
Starting December 16, the Airport Transport Service (who operate the buses under the "Friendly Airport Limousine" brand) will start a new service to selected hotels in the Akasaka and Shinjuku area, which will be an exclusive service for arriving passengers.
https://www.limousinebus.co.jp/uploads/info/2020/12/cross_border_en.pdf
A reservation and payment must be placed in advance and the passenger must be staying in one of the 12 hotels below.
【Akasaka Area】6 Hotels
The Okura Tokyo, ANA InterContinental
Tokyo, New Otani, The Prince Gallery Tokyo Kioicho, a Luxury Collection Hotel
Akasaka Excel Hotel Tokyu, The Capitol
Hotel Tokyu
【Shinjuku Area】 6
Hotels
Century Southern Tower, Hotel Sunroute
Plaza Shinjuku, Hyatt Regency Tokyo
Shinjuku Washington Hotel, Park Hyatt
Tokyo, Hilton Tokyo
The new services depart three times a day from both Narita and Haneda Airport at the following times:
From NRT: 10:00 /18:00/ 21:00 (Cost 4,000 JPY per person)
From HND: 10:00/16:05/19:45 (Cost 1,500 JPY per person)