How to Pickle Red Onions for Your Tacos

We can’t get enough pickled red onions on our tacos. They’re tangy, a bit sweet, and offer a satisfying crunch. While they seem fancy, homemade pickled onions are actually super easy to make and spice up any fiesta. With only five ingredients and a few simple steps, we’re going to walk you through everything you need to know about how to make pickled red onions. We have a feeling they’re going to become a family favorite!

Pickled red onions in a jar, whole red onions

Getting Started

First things first, let’s grab your ingredients. You’re going to need water, cider vinegar, sugar, salt, and, of course, a red onion.

In our pickled red onion recipe, we like to use cider vinegar. Why? Good question. On the vinegar sharpness scale, it’s considered medium and offers a slightly sweet, fruity flavor perfect for a red onion.

When it comes to sugar, classic white sugar (cane or beet) works great! For salt, we like to use table salt. If you’re using Kosher salt, keep in mind these salt crystals are larger than table salt, so you’ll need to use more.

How many onions you want to pickle is up to you! That, you feel with your heart. The ingredients below are for one onion, so just adjust the ingredients if you’re making more.

The classic, tasty flavors of pickled red onions jazz up any dish, but if you’re looking to take it to the next level, get creative! Spice up your recipe with dried chiles, jalapeños, peppercorns, or even fresh herbs such as dill, rosemary, or thyme.


  • 1 cup water
  • 1/2 cup cider vinegar
  • 2 tablespoons sugar
  • 1 teaspoon salt
  • 1 large red onion

Pickled Red Onion Directions


Measure out your ingredients so they’re easy to grab and add. Next, it’s time to slice that red onion. First, cut your onion in half, then from the root end to the top, thinly slice it. If you have a mandoline available, feel free to use it! Add your onion into a 10-ounce or 16-ounce jar. If you’re adding any optional flavors such as jalapenos, herbs, etc., do that now!


Add your vinegar, water, sugar, and salt into a medium-sized bowl. Next, stir until the sugar and salt dissolve; this should be around 60-seconds. Then pour over your onions, and place the jar in the fridge.


Your pickled red onions should be ready in about an hour if they were sliced thinly. If you went for a thicker slice, leave them overnight. They should look bright pink and tender!


Pick out your go-to taco recipe and add these on top. Enjoy!

The longer your pickled onions sit in the fridge, the more flavorful they’ll become. Now put your pickled red onions to the test with these recipes: