Heidelberg is a very popular destination in December, please try to reserve your accomodation as early as possible.
Hotel recommendations
A large variety of accomodation options is available on the usual booking websites.
Additional recommendations:
Hotel Vier Jahreszeiten Heidelberg (hotel close to venue, single rooms ~90-100 EUR/night, double rooms single occupancy ~110 EUR/night incl. breakfast):
https://4--jahreszeiten-de.translate.goog/?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp
GuestHouse Heidelberg (studio apartments, good value for money):
http://www.guesthouse-hd.de/ghouse/website.nsf/index.html?openpage&L=2
BS Boutique Hotel Heidelberg (modern boutique hotel, single rooms from 85 EUR/night, double 145 EUR/night):
https://bs-hotels.de/en/welcome-to-bs-boutique-hotel/
Steffis Hostel Heidelberg (hostel, private rooms from 70 EUR/night):
https://www.hostelheidelberg.de/en/index.html
