Line a large baking sheet or tray with parchment paper, wax paper, aluminum foil, or place a wire rack over a baking sheet.
Place 4 ounces red candy melts, 4 ounces royal blue candy melts, and 4 ounces white candy melts into three separate tall microwave-safe glasses or bowls.
Microwave each color in 30-second intervals, stirring after each interval, until the candy melts are completely melted and smooth.
Dip 8 pretzel rods halfway into the melted royal blue candy, allowing any excess coating to drip off before placing them on the prepared baking sheet.
Then dip 8 of the pretzels in the red candy melt and the remaining 8 in the white candy melt and place them on the cookie sheet as well.
Repeat with 8 pretzel rods dipped in the red candy melts and the remaining 8 pretzel rods dipped in the white candy melts.
While the candy coating is still wet, use a fork to drizzle the remaining melted candy colors over each pretzel rod for a festive design.
Immediately sprinkle the coated pretzel rods with red, white, and blue star sprinkles before the candy hardens.
Let the pretzel rods sit at room temperature for about 1 hour, or refrigerate for about 30 minutes, until the candy coating is completely set.
Serve immediately or store the pretzel rods in an airtight container at room temperature for up to 2 weeks.