Warning: this list is obsolete. Please check more recent posts.
Here is a new update on the 53 teams (27 Challengers, 25 Cruisers, and 1 Adventure car) aiming for the 2019 Bridgestone World Solar Challenge in Australia this coming October. Few teams have any significant news to report at this stage, so this is my best understanding of the current team status.
By special request, all links in this post (including the clickable social media icons) now open in a new tab or page, depending on your browser (I would welcome feedback on whether this is an improvement):
Adelaide University

Challenger (Lumen II) – existing car.
ATN Solar Car Team

Cruiser (new team: see my team bio) – they have manufactured several parts of the car interior.
Australian National University

Challenger (new car: MTAA Gnowee) – no details as yet.
Flinders University

Cruiser (Investigator Mark III) – existing car.
Swinburne Solar Team

Cruiser (new team) – they appear to be building their first solar car.
TAFE SA 
Cruiser (SAV) – existing car.
Team Arrow

Cruiser (ArrowSTF) – their commercial arm, Prohelion, is selling power packages.
University of New South Wales / Sunswift

Cruiser (Violet) – they set a record for lowest energy consumption driving trans-Australia (Perth to Sydney).
Western Sydney Solar Team

Challenger (Unlimited 2.0) – they won the American Solar Challenge with this car last year, and will be making further improvements.
Punch Powertrain Solar Team

Challenger (new car) – they have some (top secret) production moulds.
ETS Quebec (Eclipse)

Challenger (Éclipse X) – they came an excellent 3rd in the ASC, 102 minutes behind Western Sydney.
University of Toronto (Blue Sky)

Challenger (new car: Viridian) – they plan to unveil the new car in July.
Antakari Solar Team

Challenger (new car: Intikallpa V) – no news on the new design as yet.
Eolian AutoSolar

Cruiser (new car: Auriga ) – no news on the new design as yet.
Bochum University of Applied Sciences

Cruiser (new car) – no news on the new design as yet.
Sonnenwagen Aachen

Challenger (new car) – no details as yet.
Hong Kong Institute of Vocational Education

Cruiser (Sophie VI) – existing car.
R.V. College of Engineering

Challenger (new car) – no details as yet.
SolarMobil Manipal 
Cruiser (SM-S2) – existing car.
Futuro Solare Onlus

Cruiser (new car: Archimede 2.0) – they have an exciting design concept.
Onda Solare

Cruiser (Emilia 4) – they won the American Solar Challenge (Cruiser class) last year, and they have written up their design process here.
Kogakuin University

Challenger (new car) – they have officially announced their participation.
Nagoya Institute of Technology

Challenger (new car) – no news on the new design as yet.
Tokai University

Challenger (new car) – no news on the new design as yet.
Kookmin University Solar Team

Challenger (new car) – no news on the new design as yet.
EcoPhoton / UiTM

Challenger (new car: Tigris) – no news on the new design as yet, but Malaysia Boleh!
Mines Rabat Solar Team

Challenger (new car: Eleadora 2) – their new catamaran will look like this.
Solar Team Eindhoven

Cruiser (new car: Stella ?) – they have a good team working on the car.
Solar Team Twente

Challenger (new car) – they are already producing regular vlogs, and have a vlog for February (Dutch only).
Top Dutch Solar Racing

Challenger (new team: see my team bio) – they have been prototyping in the snow.
Vattenfall Solar Team (Delft)

Challenger (new car: Nuna X) – these are the champions formerly known as Nuon. See their name change announcement video.
Lodz Solar Team

Cruiser (Eagle Two) – they have been visiting the USA for a conference.
PUT Solar Dynamics

Cruiser (new team) – they are based in the home town of the famous Australian explorer Paweł Strzelecki.
Polytech Solar

Cruiser (new car) – no news on the new design as yet.
Singapore Polytechnic

Cruiser (new car) – no details as yet.
Chalmers Solar Team

Challenger (new team: see my team bio) – their preliminary design resembles that of the South African NWU team.
Halmstad University Solar Team

Challenger (new team: see my team bio) – they are planning a bullet car, much like Michigan’s 2017 entry.
JU Solar Team

Challenger (new car) – no news on the new design as yet.
MDH Solar Team

Challenger (new car) – some degree of autonomous driving is planned.
Solar Energy Racers

Challenger (SER-3) – they raced this car in South Africa.
Kaohsiung / Apollo

Cruiser (new car) – no news on the new design as yet.
Siam Technical College

Cruiser (new car: STC-3) – no news on the new design as yet.
Dokuz Eylül University (Solaris)

Challenger (plans uncertain) – no details as yet.
Ardingly College

Cruiser – this high-school team came 6th in the iESC Cruiser class.
Cambridge University

Cruiser (new car: Helia) – they are busy with fabrication.
Durham University

Challenger (new car: Ortus) – no news on the new design as yet.
Appalachian State University (Sunergy)

Cruiser (new team: see my team bio) – they competed in the American Solar Challenge last year, with their car ROSE.
Berkeley (CalSol)

Cruiser (new car: Tachyon) – they have a bottom shell and roll cage.
Houston School District

Adventure (Sundancer) – this high school team is a regular competitor.
Iowa State University (PrISUm)

Cruiser (new car: Eliana) – no news on the new design as yet.
Stanford Solar Car Project

Challenger (new car) – no news on the new design as yet.
University of Michigan

Challenger (new car) – they are asking for name suggestions for the new car.
University of Minnesota Solar Vehicle Project

Cruiser (new car: Freya) – no news on the new design as yet.
This page last updated 08:22 on 25 February 2019 AEDT