Question: "Should a Christian woman wear a bikini?"
Answer: As a woman, I have considered this question many times myself. Here are some verses from God's Word and some of my thoughts: God calls women to modesty, which means to not draw attention to themselves: 1 Timothy 2:9-10 says, "I also want women to dress modestly, with decency and propriety, not with braided hair or gold or pearls or expensive clothes, but with good deeds, appropriate for women who profess to worship God."
God calls us to purity: 1 Timothy 4:12 says, "Don't let anyone look down on you because you are young, but set an example for the believers in speech, in life, in love, in faith and in purity."
God calls all people to control their thought lives, so as women, we should not cause men to lust: Matthew 5:27-29 says, "You have heard that it was said, 'Do not commit adultery.' But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart." 1 John 2:16-17 says, "For everything in the world-the cravings of sinful man, the lust of his eyes and the boasting of what he has and does-comes not from the Father but from the world. The world and its desires pass away, but the man who does the will of God lives forever."
God calls women to discretion. I love this verse! Proverbs 11:22 says, "Like a gold ring in a pig's snout is a beautiful woman who shows no discretion." Your body is God's. Romans 12:1-2 says, "Therefore, I urge you, brothers, in view of God's mercy, to offer your bodies as living sacrifices, holy and pleasing to God-this is your spiritual act of worship. Do not conform any longer to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God's will is-his good, pleasing and perfect will."
I have made the commitment not to wear a bikini unless I am in a private location, like my fenced-in back yard. According to the verses above, I have the responsibility to not put the males around me in a position that they might lust or have impure thoughts (see also Matthew 18:7). Most bikinis are very small and don't cover a lot of skin...they don't leave much to the imagination!
What if I dress modestly and a man still lusts after me? I'm not responsible for that lust. In this case, the responsibility for impure thoughts lies solely on the man. So, for me, I don't wear bikinis in public as a statement of purity.