Accompanied by about one hundred Barisan Nasional (BN) and SUPP supporters, Lee arrived about 8.40am along with his proposer Law Kiu Kiong and seconder Julaihi Mohamad.
He filed his nomination at 9am.
Lee, a four-term assemblyman, was confident of his chances and said he would trust the voters to choose him for his services rendered over the past 20 years.
Bob Baru Langub of DAP, who served as a local dentist for the last 33 years, arrived with DAP Secretary-General Lim Guan Eng and about 30 DAP supporters at 8.30am.
He was accompanied by his proposer Chew Jing Ling and seconder Ruba Tagong Aran.
He filed his nomination at 9.32am
The surprise package, however, came from local-born martial arts exponent Philemon John Endau who represented PBDS-Baru.
Philemon, a mixed martial arts fighter and owner of a local martial arts academy, said he was contesting because he wanted to help his hometown folk and kinsmen.
“I want to fight for Anak Sarawak (Sarawakians),” the 39-year-old told reporters at the Miri Community Hall today.
He filed his nomination at 9.40am.
Election Commission Returning Officer for Senadin, Mohd Junaidi Mohidin, announced all three candidates at 12:05pm.
“After checking, all three candidates are qualified to contest,” he said.
The three will now have a 12-day campaign period before polling on May 7.
In 2011, Lee, current vice-president of SUPP, defeated Michael Teo of PKR by only 58 votes.
Senadin is the only state seat in Miri still controlled by BN after two others Pujut and Piasau – fell to DAP during the last state polls.