The star looked svelte in a colourful bikini, and sported a natural make-up free look as she spent the afternoon on Venice Beach, Los Angeles, kissing and cuddling dark-haired Locke, guitarist of rock band Rooney.
The pair have been dating since earlier this year, and it looks like they're going pretty steady.
Love on the beach: Mischa Barton makes her feelings for her musician boyfriend Taylor Locke pretty clear as they canoodle on LA's Venice Beach
Free-spirited Mischa recently spoke about her love life, telling the US edition of Marie Claire: 'I’m lucky to know you can have more than one soul mate in life.
'But, like a true actress, I’m always changing the way I feel about who I want to be. Nowadays, I feel I’m settling more into a woman and I’m understanding who I am.'
However, last year it seemed as though Mischa was struggling to put spoilt teen Marissa Cooper, who she played in teen drama The OC, behind her, after she was arrested for driving under the influence.
The actress was sentenced to three years probation and to complete a three-month course in alcohol education after pleading no contest to drink driving charges in April.
Beach babe: Mischa looks svelte and toned as she wore a colourful bikini on Venice Beach
Recalling the incident in the interview, Mischa admits she was shocked at her arrest, because it grouped her with other young Hollywood stars she would prefer not to be associated with.
She spoke out about the low period in the new issue of US Marie Claire: 'It was a low point in my life. I mean, the truth of the matter is, I was being irresponsible to begin with – I moved to LA and never got a license.
'I don’t know, it was just an awful low for me'.
She added: 'Even though, in a lot of ways, my upbringing has been quite liberal, something like that is embarrassing and appalling for my parents.
'It was a surreal experience and I was shocked at how much press it made but, the thing is, I apologised – and you have to just hope that that’s enough, because what else can you do? I’m just living life, and people make mistakes, you know'.
Does my bum look big in this: Mischa's boyfriend gets a little cheeky as he checks out her rear
