Should You Use Idioms in IELTS Speaking?

The answer might surprise you.

Yes, You Do Need “Idiomatic Vocabulary” —
But Not What You Think

Here’s the part that trips everyone up: the IELTS Speaking band descriptors do reward idiomatic language. Under the Lexical Resource criterion, higher band scores mention the ability to use vocabulary “with flexibility and precision” and to produce “idiomatic language” naturally.

The key word there is naturally.

Examiners are trained to tell the difference between language that flows authentically and language that has been memorised and shoe-horned into an answer. When they hear the latter, it signals poor vocabulary control — and that actually lowers your score, not raises it.

The Problem With Unusual Idioms

Many IELTS students target obscure or overly colourful idioms — the kind you find on “Top 50 IELTS Idioms” lists. Phrases like “once in a blue moon,” “spill the beans,” or “beat around the bush” might seem impressive on paper. But in a real conversation, they often sound unnatural, especially when the topic doesn’t call for them.

Think about it: when did you last hear a native speaker drop “it’s raining cats and dogs” into a serious discussion about climate change? Probably never. That’s the trap.

What to Do Instead: Focus on Sounding Natural

Here’s the good news: you don’t need to memorise lists of unusual idioms to score well. What examiners actually want to hear is natural, fluent English — the kind real people use every day.

That means focusing on three things:

• Common phrases — things like “to be honest,” “to be fair,” “what I mean is,” or “it depends, really.” These are the phrases native speakers reach for without thinking.
• Collocations — word partnerships that native speakers use naturally, such as “make a decision,” “take your time,” “strong opinion,” or “deeply concerned.” Getting collocations right is a huge signal to examiners that your English is at a high level.
• Simple expressions used well — a well-placed “that said,” “having grown up with…” or “I suppose what strikes me most is…” will impress far more than a forced idiom ever could.

Quick Dos and Don’ts

• DO use phrases you’d genuinely say in everyday conversation.
• DO practise collocations — they’re one of the fastest ways to improve your Lexical Resource score.
• DON’T memorise idiom lists and try to insert them into your answers.
• DON’T use an expression if you’re not 100% sure it fits naturally in context.

Let’s Try That Again

Once you shift your focus from impressing the examiner with unusual idioms to simply sounding like a natural English speaker, something clicks. Your answers flow better. You hesitate less. And your score reflects it.

The good news? This is a skill you can learn — and practise — systematically.

In my IELTS Speaking Course, I walk you through exactly which common phrases, collocations, and natural expressions to use — and how to use them with confidence in every part of the Speaking test. No cramming odd idioms. No sounding robotic. Just real, natural English that gets results.