Only Orthodox conversion are allowed in Israel, elsewhere the rules have been relaxed..... slightly:
"For instance the female convert (giyoret) today may wear a loosely fitting smock during immersion. This satisfies the requirement that the water of the mikveh should be in contact with all parts of the body, while avoiding embarrassment to the convert or the three rabbis who must witness the act" source
"After reciting a blessing, the convert is immersed in the water. In accordance with Jewish law, the immersion must be witnessed by three attendants. Emerging from the mikveh, a convert is now Jewish." source