The SAR swimmer, who is ramping up training for this September’s Asian Games in Japan with high-level international meets, finished atop the podium in the women’s 200-metre freestyle.
Haugher held off a hard-charging Erika Fairweather of New Zealand over the final 50 metres to touch the wall in one minute, 55.22 seconds.
Fairweather was close behind in second at one minute, 55.49 seconds, while Barbora Seemanova of the Czech Republic rounded out the podium.
The win was Haughey’s second medal in Barcelona, having also won silver in the women’s 50-metre freestyle earlier in the day at 24.45 seconds, 0.12 seconds off the pace of Dutch winner Milou van Wijk.
In all, Haughey has won four golds and four silvers at this year’s Mare Nostrum meet, which began in Monaco, with a second leg in France before the final leg in Spain.