Updated 13 July 2019 - Changes in red
Updated 16 Dec 2019 - Changes in green

The official "how to" is here but below are the details :

Argentina
No longer available

Australia
1300 135 604
Monday-Friday:9:00 am to 5:30 pm AEST

Belgique
027 007 272
du lundi au vendredi de 09h00 à 17h30

België
027007270
Maandag: 09:00 tot 17:30
Dinsdag t/m vrijdag: 09:00 tot 16:30

Brasil
A partir de telefone fixo (grátis) 0800-892-1259
A partir de celular (aplica-se as taxas de sua operadora) 1147002436
De Segunda a Sexta: das 6.00 às 12.30. BRT
Para que consiga entrar em contato conosco, aconselhamos que utilize preferencialmente um telefone fixo.

Canada (en)
+1 877-757-7137
Monday - Friday: 9:00 a.m. to 6:00 p.m. EST

Canada (fr)
+1 888 301 0690
lundi-vendredi: 06h00-11h30 EDT

Ceská Republika
Now Chat only
Hodiny pro konverzaci jsou uvedeny dále.
Pondelí - Pátek: 09:00 dop. - 05:30 odp. CEST
Sobota - Nedele: Uzavreno
Aktuální stav je Sobota 13. Cvc 2019 11:16 dop. CEST

Chile
No longer available

China
4006701100
Customer Service Hours: Monday to Friday 09:00-17:00 (holidays will not be served)

Danmark
Now Chat only
Chattimerne er angivet nedenfor.
Mandag - Fredag: 09:00 Formiddag - 05:30 Eftermiddag CEST
Lørdag - Søndag: Lukket

Deutschland
+49 89 143 77 0272
Mo - Fr: 09:00 - 17:30

Eesti (Estonia) [in English only]
8000044381
Monday-Friday: 11:00-19:00

España (Spain)
913496508
Lunes-Viernes: 09:00-17:30

France
01 70 36 35 82
du lundi au vendredi de 09h00 à 17h30

Greece
0080044144676
Monday - Friday: 10:30 - 14:30

India
Email only

Indonesia (uses Australian office)
001611300 135 604
Monday-Friday: 9:00 am to 5:30 pm AEST

Email: [email protected]

Ireland
1890 812 008
Monday-Friday: 09:00 am to 5:00 pm

Italia
0245281004
lunedì-venerdì: ore 09:00-17:30 CET

Japan
Email only

Korea
Email only

Latvija [in English only]
800 034 46
Monday-Friday:11:00-19:00

Lietuva (Lithuania) [in English only]
880 03 08 96
Monday-Friday: 10:00-18:00

Luxembourg
+33 1 7036 3582
lundi-vendredi: 10h00-17h30

Magyarország (Hungary)
0036 177 792 27
hétfo-péntek: 09:00-17:00

Malaysia
1800815318
Monday-Friday: 07:30-14:30

Maroc
Maroc: email seulement

México
Email only

Nederland (Holland)
020 850 1022
Maandag t/m vrijdag : 09:00 tot 17:30

New Zealand
+6499055597
Monday-Friday: 11:00-19:30 NZST

Norge (Norway)
Now Chat only
Du finner en oversikt over chattetider nedenfor.
Mandag - Fredag: 09:00 AM - 05:30 PM CEST
Lørdag - Søndag: Lukket
Det er nå Lørdag, Jul 13, 2019 11:45 AM CEST

Österreich (Austria)
08101 02 557
Montag bis Freitags von 09:00 bis 17:30 Uhr


Polska (Poland)
+48 22 30 62 335
Poniedzialek-Piatek: 9.00- 17.00

Portugal
800780277
De Segunda a Sexta: das 08.00 às 16.30

Russia
Email only

Schweiz (Switzerland)
08440 000 16
Mo: 09:00 - 17:30
Di - Fr: 09:00 - 16:30

Singapore
1800 622 7266
Monday - Friday: 09:00 - 17:30

South Africa
0800 980670
Monday-Friday: 10:00 to 18:30

Suisse (Switzerland)
0844000091
du lundi au vendredi de 09h00 à 17h30

Suomi (Finland)
Now Chat only
Keskustelutunnit on lueteltu alla.
Maanantai - Perjantai: 10:00 AM - 06:30 PM EEST
Lauantai - Sunnuntai: Suljettu

Sverige (Sweden)
Now Chat only
Chattimmarna visas i nedanstående lista.
Måndag - Fredag: 09:00 AM - 05:30 PM CEST
Lördag - Söndag: Stängt

Türkiye
No longer available

Taiwan
0800-601-000
Monday to Friday 09: 00-17: 00

United Kingdom
02079 490 134
Monday - Friday: 9:00 a.m. to 5:30 p.m.

United States
877-757-7137
Monday - Friday: 9:30 a.m. to 6:00 p.m. EST

All other countries
+31208501004
Monday-Friday: 9:00 to 17:30 GMT

Information above taken from TomTom's various support sites 13/07/2019