Some of the websites mentioned in the other sections specifically educate on the important role of sun-protective clothing, such as this section from the Skin Cancer Foundation:
The link below has a really good list of companies specializing in sun-protective clothing! We have no stake in any of the companies listed here, but are aiming to make this site as practical and user-friendly as possible! Please feel free to contact us if you have any other links to products you have tried and highly recommend to fellow tennis players!
The following article has another useful list of several additional companies offering stylish sun-protective clothing:
Please note that most of the major tennis online sellers have sections now for "UV Protection Apparel" or "UV-Protective Clothing" (e.g. www.tenniswarehouse.com, www.tennis-point.com, www.tennisexpress.com, www.tennisplaza.com, www.dickssportinggoods.com, www.doittennis.com, www.nike.com, etc. Inexpensive sun protective clothing can also be found at www.walmart.com and www.amazon.com
PLEASE NOTE that some of the best sun protective clothing can be found outside of the tennis universe, especially in websites or stores focusing on GOLF. In many ways, golfers are a step ahead of tennis players when it comes to wearing UV-protective sleeves, which can help to prevent skin cancer and premature aging on your arms, and should be used more and more by tennis players as well! (www.uvoider.com, https://www.independentgolfreviews.com/best-sun-sleeves/ )