While the trench coat and pea coat are both timeless outerwear designed to protect from the elements, each have their own unique aesthetic, history, and functional purposes and, in general, are not interchangeable either from a style stand point or utility stand point.
Pea Coat
(Also spelled peacoat without the space.)
Origin:
The pea coat has a rich naval history going back to the 18th century, originally worn by sailors and seamen in European navies. The name pea coat is believed to be a “calque,” or phonetic borrowing, from the Dutch word “pij” which referred to a course woolen cloth.
Design:
A predominant difference between pea coats and trench coats are their length and material. Pea coats end just below the hips or no longer than mid-thigh, whereas trench coats extend beyond the knee.
Pea coats, while not exclusively, are almost always made of wool or a synthetic blend that mimics the texture and thickness of wool.
The pea coat's design is visually defined by its double-breasted front closure. A double-breasted coat or jacket features two parallel vertical columns of buttons with an overlapping front flap, providing a distinctive and formal appearance.
The pea coat design has been losing buttons since World War I, where they often had 10, later 8, and now usually 6. The buttons of a pea coat are large and substantive, likely to aid in fastening during inclement weather while wearing gloves. Buttons are nowadays usually black, but some more naval-inspired coats may have gold ones.
Due to their naval heritage, it should be no surprise that traditional pea coats are navy blue, though contemporary versions can be had in almost any color or material.
→ Fun fact: The US Navy began phasing out the peacoat in 2018, replacing it with a black synthetic parka.
Core Competency:
Providing warmth in winter temperatures.
Trench Coat
Origin:
The trench coat was an evolution of a 19th century raincoat known as a Mackintosh or ‘mac’ coat. The trench coat’s design is often credited to Thomas Burberry – yes, of that Burberry – who invented the water-resistant gabardine fabric.
Unlike waxed canvas, a fabric where the waterproofing comes from a wax applied to the surface of woven cotton, gabardine's water resistance comes from its tight weave, plus any additional water resistance treatments. This fundamental difference in treatment results in unique characteristics for each fabric: Waxed canvas is heavier and develops a distinctive patina over time, while gabardine offers a smoother finish and is favored for its versatility in more refined pieces.
The resulting coat was a lighter, more practical option for World War I officers in the trenches, thus the name.
→ Fun fact: Superman’s cape, as played by Christopher Reeve, was also made of gabardine.
Design:
Trench coats are long, extending to the knees or even lower, and are made of gabardine, as mentioned, or other similar water-resistant fabrics and blends in modern versions. They can be either single or double breasted, and feature an iconic waist belt, massive lapels, shoulder epaulettes, and a “storm flap” over the right shoulder to direct water away from the body.
Trench coats most famously come in “1930s Detective Tan” and “Not-so-popular in School Black“.
Core Competency:
Protection from precipitation and wind.
Pea Coat vs Trench Coat Comparison
Function: A pea coat is predominantly a fall and winter coat with the goal of keeping the wearer warm. A trench coat is generally a spring coat intended to protect the wearer from heavy wind and rain.
Style: Both coats are classic menswear choices steeped in military history and heritage, and both can be worn by well-dressed men in both casual and more dressed-up scenarios. However, the trench coat can be more challenging to pull off day-to-day for novices, especially outside of rainy spring days, whereas every guy from the leading moving actors to even the most poorly dressed schlub can wear a pea coat effortlessly. For this reason, the entry-level style option is the pea coat.